diff --git a/InvenTree/InvenTree/filters.py b/InvenTree/InvenTree/filters.py
index cd1b769646..94e6e1765b 100644
--- a/InvenTree/InvenTree/filters.py
+++ b/InvenTree/InvenTree/filters.py
@@ -34,18 +34,47 @@ class InvenTreeOrderingFilter(OrderingFilter):
             Ordering fields should be mapped to separate fields
             """
 
-            for idx, field in enumerate(ordering):
+            ordering_initial = ordering
+            ordering = []
 
-                reverse = False
+            for field in ordering_initial:
+                
+                reverse = field.startswith('-')
 
-                if field.startswith('-'):
+                if reverse:
                     field = field[1:]
-                    reverse = True
 
+                # Are aliases defined for this field?
                 if field in aliases:
-                    ordering[idx] = aliases[field]
+                    alias = aliases[field]
+                else:
+                    alias = field
 
+                """
+                Potentially, a single field could be "aliased" to multiple field,
+                
+                (For example to enforce a particular ordering sequence)
+
+                e.g. to filter first by the integer value...
+
+                ordering_field_aliases = {
+                    "reference": ["integer_ref", "reference"]
+                }
+
+                """
+
+                if type(alias) is str:
+                    alias = [alias]
+                elif type(alias) in [list, tuple]:
+                    pass
+                else:
+                    # Unsupported alias type
+                    continue
+
+                for a in alias:
                     if reverse:
-                        ordering[idx] = '-' + ordering[idx]
+                        a = '-' + a
+
+                    ordering.append(a)
 
         return ordering
diff --git a/InvenTree/InvenTree/locale_stats.json b/InvenTree/InvenTree/locale_stats.json
deleted file mode 100644
index 9f003895c5..0000000000
--- a/InvenTree/InvenTree/locale_stats.json
+++ /dev/null
@@ -1 +0,0 @@
-{"de": 95, "el": 0, "en": 0, "es": 4, "fr": 6, "he": 0, "id": 0, "it": 0, "ja": 4, "ko": 0, "nl": 0, "no": 0, "pl": 27, "ru": 6, "sv": 0, "th": 0, "tr": 32, "vi": 0, "zh": 1}
\ No newline at end of file
diff --git a/InvenTree/InvenTree/models.py b/InvenTree/InvenTree/models.py
index 2ca179bb40..0f8350f84f 100644
--- a/InvenTree/InvenTree/models.py
+++ b/InvenTree/InvenTree/models.py
@@ -4,6 +4,7 @@ Generic models which provide extra functionality over base Django model types.
 
 from __future__ import unicode_literals
 
+import re
 import os
 import logging
 
@@ -43,6 +44,48 @@ def rename_attachment(instance, filename):
     return os.path.join(instance.getSubdir(), filename)
 
 
+class ReferenceIndexingMixin(models.Model):
+    """
+    A mixin for keeping track of numerical copies of the "reference" field.
+
+    Here, we attempt to convert a "reference" field value (char) to an integer,
+    for performing fast natural sorting.
+
+    This requires extra database space (due to the extra table column),
+    but is required as not all supported database backends provide equivalent casting.
+
+    This mixin adds a field named 'reference_int'.
+
+    - If the 'reference' field can be cast to an integer, it is stored here
+    - If the 'reference' field *starts* with an integer, it is stored here
+    - Otherwise, we store zero
+    """
+
+    class Meta:
+        abstract = True
+
+    def rebuild_reference_field(self):
+
+        reference = getattr(self, 'reference', '')
+
+        # Default value if we cannot convert to an integer
+        ref_int = 0
+
+        # Look at the start of the string - can it be "integerized"?
+        result = re.match(r"^(\d+)", reference)
+
+        if result and len(result.groups()) == 1:
+            ref = result.groups()[0]
+            try:
+                ref_int = int(ref)
+            except:
+                ref_int = 0
+
+        self.reference_int = ref_int
+
+    reference_int = models.IntegerField(default=0)
+
+
 class InvenTreeAttachment(models.Model):
     """ Provides an abstracted class for managing file attachments.
 
diff --git a/InvenTree/InvenTree/static/css/inventree.css b/InvenTree/InvenTree/static/css/inventree.css
index 71e518560b..eca502425a 100644
--- a/InvenTree/InvenTree/static/css/inventree.css
+++ b/InvenTree/InvenTree/static/css/inventree.css
@@ -455,6 +455,10 @@
     -webkit-opacity: 10%;
 }
 
+.table-condensed {
+    font-size: 90%;
+}
+
 /* grid display for part images */
 
 .table-img-grid tr {
diff --git a/InvenTree/InvenTree/validators.py b/InvenTree/InvenTree/validators.py
index 1b6a6b3f0b..76d485cef9 100644
--- a/InvenTree/InvenTree/validators.py
+++ b/InvenTree/InvenTree/validators.py
@@ -5,6 +5,7 @@ Custom field validators for InvenTree
 from django.conf import settings
 from django.core.exceptions import ValidationError
 from django.utils.translation import gettext_lazy as _
+from django.core.exceptions import FieldDoesNotExist
 
 from moneyed import CURRENCIES
 
@@ -156,3 +157,33 @@ def validate_overage(value):
     raise ValidationError(
         _("Overage must be an integer value or a percentage")
     )
+
+
+def validate_part_name_format(self):
+    """
+    Validate part name format.
+    Make sure that each template container has a field of Part Model
+    """
+
+    jinja_template_regex = re.compile('{{.*?}}')
+    field_name_regex = re.compile('(?<=part\\.)[A-z]+')
+    for jinja_template in jinja_template_regex.findall(str(self)):
+        # make sure at least one and only one field is present inside the parser
+        field_names = field_name_regex.findall(jinja_template)
+        if len(field_names) < 1:
+            raise ValidationError({
+                'value': 'At least one field must be present inside a jinja template container i.e {{}}'
+            })
+
+        # Make sure that the field_name exists in Part model
+        from part.models import Part
+
+        for field_name in field_names:
+            try:
+                Part._meta.get_field(field_name)
+            except FieldDoesNotExist:
+                raise ValidationError({
+                    'value': f'{field_name} does not exist in Part Model'
+                })
+
+    return True
diff --git a/InvenTree/build/admin.py b/InvenTree/build/admin.py
index 86592c7a81..a5ad838660 100644
--- a/InvenTree/build/admin.py
+++ b/InvenTree/build/admin.py
@@ -9,6 +9,10 @@ from .models import Build, BuildItem
 
 class BuildAdmin(ImportExportModelAdmin):
 
+    exclude = [
+        'reference_int',
+    ]
+
     list_display = (
         'reference',
         'title',
diff --git a/InvenTree/build/api.py b/InvenTree/build/api.py
index cc897d6ec9..cf4d44a03e 100644
--- a/InvenTree/build/api.py
+++ b/InvenTree/build/api.py
@@ -17,11 +17,12 @@ from django_filters import rest_framework as rest_filters
 
 from InvenTree.api import AttachmentMixin
 from InvenTree.helpers import str2bool, isNull
+from InvenTree.filters import InvenTreeOrderingFilter
 from InvenTree.status_codes import BuildStatus
 
 from .models import Build, BuildItem, BuildOrderAttachment
 from .serializers import BuildAttachmentSerializer, BuildSerializer, BuildItemSerializer
-from .serializers import BuildAllocationSerializer
+from .serializers import BuildAllocationSerializer, BuildUnallocationSerializer
 
 
 class BuildFilter(rest_filters.FilterSet):
@@ -68,7 +69,7 @@ class BuildList(generics.ListCreateAPIView):
     filter_backends = [
         DjangoFilterBackend,
         filters.SearchFilter,
-        filters.OrderingFilter,
+        InvenTreeOrderingFilter,
     ]
 
     ordering_fields = [
@@ -83,6 +84,10 @@ class BuildList(generics.ListCreateAPIView):
         'responsible',
     ]
 
+    ordering_field_aliases = {
+        'reference': ['reference_int', 'reference'],
+    }
+
     search_fields = [
         'reference',
         'part__name',
@@ -184,6 +189,42 @@ class BuildDetail(generics.RetrieveUpdateAPIView):
     serializer_class = BuildSerializer
 
 
+class BuildUnallocate(generics.CreateAPIView):
+    """
+    API endpoint for unallocating stock items from a build order
+
+    - The BuildOrder object is specified by the URL
+    - "output" (StockItem) can optionally be specified
+    - "bom_item" can optionally be specified
+    """
+
+    queryset = Build.objects.none()
+
+    serializer_class = BuildUnallocationSerializer
+
+    def get_build(self):
+        """
+        Returns the BuildOrder associated with this API endpoint
+        """
+
+        pk = self.kwargs.get('pk', None)
+
+        try:
+            build = Build.objects.get(pk=pk)
+        except (ValueError, Build.DoesNotExist):
+            raise ValidationError(_("Matching build order does not exist"))
+
+        return build
+
+    def get_serializer_context(self):
+
+        ctx = super().get_serializer_context()
+        ctx['build'] = self.get_build()
+        ctx['request'] = self.request
+
+        return ctx
+
+
 class BuildAllocate(generics.CreateAPIView):
     """
     API endpoint to allocate stock items to a build order
@@ -349,6 +390,7 @@ build_api_urls = [
     # Build Detail
     url(r'^(?P<pk>\d+)/', include([
         url(r'^allocate/', BuildAllocate.as_view(), name='api-build-allocate'),
+        url(r'^unallocate/', BuildUnallocate.as_view(), name='api-build-unallocate'),
         url(r'^.*$', BuildDetail.as_view(), name='api-build-detail'),
     ])),
 
diff --git a/InvenTree/build/forms.py b/InvenTree/build/forms.py
index b3f6cd92de..bc7bdd50f5 100644
--- a/InvenTree/build/forms.py
+++ b/InvenTree/build/forms.py
@@ -137,32 +137,6 @@ class BuildOutputDeleteForm(HelperForm):
         ]
 
 
-class UnallocateBuildForm(HelperForm):
-    """
-    Form for auto-de-allocation of stock from a build
-    """
-
-    confirm = forms.BooleanField(required=False, label=_('Confirm'), help_text=_('Confirm unallocation of stock'))
-
-    output_id = forms.IntegerField(
-        required=False,
-        widget=forms.HiddenInput()
-    )
-
-    part_id = forms.IntegerField(
-        required=False,
-        widget=forms.HiddenInput(),
-    )
-
-    class Meta:
-        model = Build
-        fields = [
-            'confirm',
-            'output_id',
-            'part_id',
-        ]
-
-
 class CompleteBuildForm(HelperForm):
     """
     Form for marking a build as complete
diff --git a/InvenTree/build/migrations/0031_build_reference_int.py b/InvenTree/build/migrations/0031_build_reference_int.py
new file mode 100644
index 0000000000..c7fc2c16cc
--- /dev/null
+++ b/InvenTree/build/migrations/0031_build_reference_int.py
@@ -0,0 +1,18 @@
+# Generated by Django 3.2.5 on 2021-10-14 06:23
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('build', '0030_alter_build_reference'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='build',
+            name='reference_int',
+            field=models.IntegerField(default=0),
+        ),
+    ]
diff --git a/InvenTree/build/migrations/0032_auto_20211014_0632.py b/InvenTree/build/migrations/0032_auto_20211014_0632.py
new file mode 100644
index 0000000000..3dac2b30c6
--- /dev/null
+++ b/InvenTree/build/migrations/0032_auto_20211014_0632.py
@@ -0,0 +1,50 @@
+# Generated by Django 3.2.5 on 2021-10-14 06:32
+
+import re
+
+from django.db import migrations
+
+
+def build_refs(apps, schema_editor):
+    """
+    Rebuild the integer "reference fields" for existing Build objects
+    """
+
+    BuildOrder = apps.get_model('build', 'build')
+
+    for build in BuildOrder.objects.all():
+
+        ref = 0
+
+        result = re.match(r"^(\d+)", build.reference)
+
+        if result and len(result.groups()) == 1:
+            try:
+                ref = int(result.groups()[0])
+            except:
+                ref = 0
+
+        build.reference_int = ref
+        build.save()
+
+def unbuild_refs(apps, schema_editor):
+    """
+    Provided only for reverse migration compatibility
+    """
+    pass
+
+
+class Migration(migrations.Migration):
+
+    atomic = False
+
+    dependencies = [
+        ('build', '0031_build_reference_int'),
+    ]
+
+    operations = [
+        migrations.RunPython(
+            build_refs,
+            reverse_code=unbuild_refs
+        )
+    ]
diff --git a/InvenTree/build/models.py b/InvenTree/build/models.py
index 9a7b40b52f..c477794e8c 100644
--- a/InvenTree/build/models.py
+++ b/InvenTree/build/models.py
@@ -28,7 +28,7 @@ from mptt.exceptions import InvalidMove
 from InvenTree.status_codes import BuildStatus, StockStatus, StockHistoryCode
 from InvenTree.helpers import increment, getSetting, normalize, MakeBarcode
 from InvenTree.validators import validate_build_order_reference
-from InvenTree.models import InvenTreeAttachment
+from InvenTree.models import InvenTreeAttachment, ReferenceIndexingMixin
 
 import common.models
 
@@ -69,7 +69,7 @@ def get_next_build_number():
     return reference
 
 
-class Build(MPTTModel):
+class Build(MPTTModel, ReferenceIndexingMixin):
     """ A Build object organises the creation of new StockItem objects from other existing StockItem objects.
 
     Attributes:
@@ -108,6 +108,8 @@ class Build(MPTTModel):
 
     def save(self, *args, **kwargs):
 
+        self.rebuild_reference_field()
+
         try:
             super().save(*args, **kwargs)
         except InvalidMove:
@@ -587,9 +589,13 @@ class Build(MPTTModel):
         self.save()
 
     @transaction.atomic
-    def unallocateOutput(self, output, part=None):
+    def unallocateStock(self, bom_item=None, output=None):
         """
-        Unallocate all stock which are allocated against the provided "output" (StockItem)
+        Unallocate stock from this Build
+
+        arguments:
+            - bom_item: Specify a particular BomItem to unallocate stock against
+            - output: Specify a particular StockItem (output) to unallocate stock against
         """
 
         allocations = BuildItem.objects.filter(
@@ -597,34 +603,8 @@ class Build(MPTTModel):
             install_into=output
         )
 
-        if part:
-            allocations = allocations.filter(stock_item__part=part)
-
-        allocations.delete()
-
-    @transaction.atomic
-    def unallocateUntracked(self, part=None):
-        """
-        Unallocate all "untracked" stock
-        """
-
-        allocations = BuildItem.objects.filter(
-            build=self,
-            install_into=None
-        )
-
-        if part:
-            allocations = allocations.filter(stock_item__part=part)
-
-        allocations.delete()
-
-    @transaction.atomic
-    def unallocateAll(self):
-        """
-        Deletes all stock allocations for this build.
-        """
-
-        allocations = BuildItem.objects.filter(build=self)
+        if bom_item:
+            allocations = allocations.filter(bom_item=bom_item)
 
         allocations.delete()
 
@@ -720,7 +700,7 @@ class Build(MPTTModel):
             raise ValidationError(_("Build output does not match Build Order"))
 
         # Unallocate all build items against the output
-        self.unallocateOutput(output)
+        self.unallocateStock(output=output)
 
         # Remove the build output from the database
         output.delete()
@@ -1153,16 +1133,12 @@ class BuildItem(models.Model):
                 i) The sub_part points to the same part as the referenced StockItem
                 ii) The BomItem allows variants and the part referenced by the StockItem
                     is a variant of the sub_part referenced by the BomItem
+                iii) The Part referenced by the StockItem is a valid substitute for the BomItem
             """
 
             if self.build and self.build.part == self.bom_item.part:
 
-                # Check that the sub_part points to the stock_item (either directly or via a variant)
-                if self.bom_item.sub_part == self.stock_item.part:
-                    bom_item_valid = True
-
-                elif self.bom_item.allow_variants and self.stock_item.part in self.bom_item.sub_part.get_descendants(include_self=False):
-                    bom_item_valid = True
+                bom_item_valid = self.bom_item.is_stock_item_valid(self.stock_item)
 
         # If the existing BomItem is *not* valid, try to find a match
         if not bom_item_valid:
diff --git a/InvenTree/build/serializers.py b/InvenTree/build/serializers.py
index 53e71dbd27..547f565905 100644
--- a/InvenTree/build/serializers.py
+++ b/InvenTree/build/serializers.py
@@ -120,6 +120,61 @@ class BuildSerializer(InvenTreeModelSerializer):
         ]
 
 
+class BuildUnallocationSerializer(serializers.Serializer):
+    """
+    DRF serializer for unallocating stock from a BuildOrder
+
+    Allocated stock can be unallocated with a number of filters:
+
+    - output: Filter against a particular build output (blank = untracked stock)
+    - bom_item: Filter against a particular BOM line item
+
+    """
+
+    bom_item = serializers.PrimaryKeyRelatedField(
+        queryset=BomItem.objects.all(),
+        many=False,
+        allow_null=True,
+        required=False,
+        label=_('BOM Item'),
+    )
+
+    output = serializers.PrimaryKeyRelatedField(
+        queryset=StockItem.objects.filter(
+            is_building=True,
+        ),
+        many=False,
+        allow_null=True,
+        required=False,
+        label=_("Build output"),
+    )
+
+    def validate_output(self, stock_item):
+
+        # Stock item must point to the same build order!
+        build = self.context['build']
+
+        if stock_item and stock_item.build != build:
+            raise ValidationError(_("Build output must point to the same build"))
+
+        return stock_item
+
+    def save(self):
+        """
+        'Save' the serializer data.
+        This performs the actual unallocation against the build order
+        """
+
+        build = self.context['build']
+
+        data = self.validated_data
+
+        build.unallocateStock(
+            bom_item=data['bom_item'],
+            output=data['output']
+        )
+
+
 class BuildAllocationItemSerializer(serializers.Serializer):
     """
     A serializer for allocating a single stock item against a build order
diff --git a/InvenTree/build/templates/build/detail.html b/InvenTree/build/templates/build/detail.html
index 8fb259f8a4..cfba2046e3 100644
--- a/InvenTree/build/templates/build/detail.html
+++ b/InvenTree/build/templates/build/detail.html
@@ -197,7 +197,7 @@
                     <button id='allocate-selected-items' class='btn btn-success' title='{% trans "Allocate selected items" %}'>
                         <span class='fas fa-sign-in-alt'></span>
                     </button>
-                    <div class='filter-list' id='filter-list-build-items'>
+                    <div class='filter-list' id='filter-list-builditems'>
                         <!-- Empty div for table filters-->
                     </div>
                 </div>
@@ -462,12 +462,9 @@ $("#btn-auto-allocate").on('click', function() {
 });
 
 $('#btn-unallocate').on('click', function() {
-    launchModalForm(
-        "{% url 'build-unallocate' build.id %}",
-        {
-            success: reloadTable,
-        }
-    );
+    unallocateStock({{ build.id }}, {
+        table: '#allocation-table-untracked',
+    });
 });
 
 $('#allocate-selected-items').click(function() {
diff --git a/InvenTree/build/templates/build/unallocate.html b/InvenTree/build/templates/build/unallocate.html
deleted file mode 100644
index a650e95718..0000000000
--- a/InvenTree/build/templates/build/unallocate.html
+++ /dev/null
@@ -1,15 +0,0 @@
-{% extends "modal_form.html" %}
-{% load i18n %}
-{% load inventree_extras %}
-{% block pre_form_content %}
-
-{{ block.super }}
-
-
-<div class='alert alert-block alert-danger'>
-    {% trans "Are you sure you wish to unallocate all stock for this build?" %}
-    <br>
-    {% trans "All incomplete stock allocations will be removed from the build" %}
-</div>
-
-{% endblock %}
\ No newline at end of file
diff --git a/InvenTree/build/test_build.py b/InvenTree/build/test_build.py
index 04b46bbd26..df6253362e 100644
--- a/InvenTree/build/test_build.py
+++ b/InvenTree/build/test_build.py
@@ -118,6 +118,26 @@ class BuildTest(TestCase):
 
         self.stock_3_1 = StockItem.objects.create(part=self.sub_part_3, quantity=1000)
 
+    def test_ref_int(self):
+        """
+        Test the "integer reference" field used for natural sorting
+        """
+
+        for ii in range(10):
+            build = Build(
+                reference=f"{ii}_abcde",
+                quantity=1,
+                part=self.assembly,
+                title="Making some parts"
+            )
+
+            self.assertEqual(build.reference_int, 0)
+
+            build.save()
+
+            # After saving, the integer reference should have been updated
+            self.assertEqual(build.reference_int, ii)
+
     def test_init(self):
         # Perform some basic tests before we start the ball rolling
 
@@ -250,7 +270,7 @@ class BuildTest(TestCase):
 
         self.assertEqual(len(unallocated), 1)
 
-        self.build.unallocateUntracked()
+        self.build.unallocateStock()
 
         unallocated = self.build.unallocatedParts(None)
 
diff --git a/InvenTree/build/tests.py b/InvenTree/build/tests.py
index 93c6bfd511..7b2568b1c7 100644
--- a/InvenTree/build/tests.py
+++ b/InvenTree/build/tests.py
@@ -323,22 +323,3 @@ class TestBuildViews(TestCase):
 
         b = Build.objects.get(pk=1)
         self.assertEqual(b.status, 30)  # Build status is now CANCELLED
-
-    def test_build_unallocate(self):
-        """ Test the build unallocation view (ajax form) """
-
-        url = reverse('build-unallocate', args=(1,))
-
-        # Test without confirmation
-        response = self.client.post(url, HTTP_X_REQUESTED_WITH='XMLHttpRequest')
-        self.assertEqual(response.status_code, 200)
-
-        data = json.loads(response.content)
-        self.assertFalse(data['form_valid'])
-
-        # Test with confirmation
-        response = self.client.post(url, {'confirm': 1}, HTTP_X_REQUESTED_WITH='XMLHttpRequest')
-        self.assertEqual(response.status_code, 200)
-
-        data = json.loads(response.content)
-        self.assertTrue(data['form_valid'])
diff --git a/InvenTree/build/urls.py b/InvenTree/build/urls.py
index 050c32209b..d80b16056c 100644
--- a/InvenTree/build/urls.py
+++ b/InvenTree/build/urls.py
@@ -12,7 +12,6 @@ build_detail_urls = [
     url(r'^create-output/', views.BuildOutputCreate.as_view(), name='build-output-create'),
     url(r'^delete-output/', views.BuildOutputDelete.as_view(), name='build-output-delete'),
     url(r'^complete-output/', views.BuildOutputComplete.as_view(), name='build-output-complete'),
-    url(r'^unallocate/', views.BuildUnallocate.as_view(), name='build-unallocate'),
     url(r'^complete/', views.BuildComplete.as_view(), name='build-complete'),
 
     url(r'^.*$', views.BuildDetail.as_view(), name='build-detail'),
diff --git a/InvenTree/build/views.py b/InvenTree/build/views.py
index 702b3b3596..8c63c1296c 100644
--- a/InvenTree/build/views.py
+++ b/InvenTree/build/views.py
@@ -10,14 +10,13 @@ from django.core.exceptions import ValidationError
 from django.views.generic import DetailView, ListView
 from django.forms import HiddenInput
 
-from part.models import Part
 from .models import Build
 from . import forms
 from stock.models import StockLocation, StockItem
 
 from InvenTree.views import AjaxUpdateView, AjaxDeleteView
 from InvenTree.views import InvenTreeRoleMixin
-from InvenTree.helpers import str2bool, extract_serial_numbers, isNull
+from InvenTree.helpers import str2bool, extract_serial_numbers
 from InvenTree.status_codes import BuildStatus, StockStatus
 
 
@@ -246,88 +245,6 @@ class BuildOutputDelete(AjaxUpdateView):
         }
 
 
-class BuildUnallocate(AjaxUpdateView):
-    """ View to un-allocate all parts from a build.
-
-    Provides a simple confirmation dialog with a BooleanField checkbox.
-    """
-
-    model = Build
-    form_class = forms.UnallocateBuildForm
-    ajax_form_title = _("Unallocate Stock")
-    ajax_template_name = "build/unallocate.html"
-
-    def get_initial(self):
-
-        initials = super().get_initial()
-
-        # Pointing to a particular build output?
-        output = self.get_param('output')
-
-        if output:
-            initials['output_id'] = output
-
-        # Pointing to a particular part?
-        part = self.get_param('part')
-
-        if part:
-            initials['part_id'] = part
-
-        return initials
-
-    def post(self, request, *args, **kwargs):
-
-        build = self.get_object()
-        form = self.get_form()
-
-        confirm = request.POST.get('confirm', False)
-
-        output_id = request.POST.get('output_id', None)
-
-        if output_id:
-
-            # If a "null" output is provided, we are trying to unallocate "untracked" stock
-            if isNull(output_id):
-                output = None
-            else:
-                try:
-                    output = StockItem.objects.get(pk=output_id)
-                except (ValueError, StockItem.DoesNotExist):
-                    output = None
-
-        part_id = request.POST.get('part_id', None)
-
-        try:
-            part = Part.objects.get(pk=part_id)
-        except (ValueError, Part.DoesNotExist):
-            part = None
-
-        valid = False
-
-        if confirm is False:
-            form.add_error('confirm', _('Confirm unallocation of build stock'))
-            form.add_error(None, _('Check the confirmation box'))
-        else:
-
-            valid = True
-
-            # Unallocate the entire build
-            if not output_id:
-                build.unallocateAll()
-            # Unallocate a single output
-            elif output:
-                build.unallocateOutput(output, part=part)
-            # Unallocate "untracked" parts
-            else:
-                build.unallocateUntracked(part=part)
-
-        data = {
-            'form_valid': valid,
-        }
-
-        return self.renderJsonResponse(request, form, data)
-
-
 class BuildComplete(AjaxUpdateView):
     """
     View to mark the build as complete.
diff --git a/InvenTree/common/models.py b/InvenTree/common/models.py
index b9b7d9e20d..d4f26af739 100644
--- a/InvenTree/common/models.py
+++ b/InvenTree/common/models.py
@@ -25,6 +25,7 @@ from django.core.exceptions import ValidationError
 
 import InvenTree.helpers
 import InvenTree.fields
+import InvenTree.validators
 
 import logging
 
@@ -702,6 +703,14 @@ class InvenTreeSetting(BaseInvenTreeSetting):
             'validator': bool
         },
 
+        'PART_NAME_FORMAT': {
+            'name': _('Part Name Display Format'),
+            'description': _('Format to display the part name'),
+            'default': "{{ part.IPN if part.IPN }}{{ ' | ' if part.IPN }}{{ part.name }}{{ ' | ' if part.revision }}"
+                       "{{ part.revision if part.revision }}",
+            'validator': InvenTree.validators.validate_part_name_format
+        },
+
         'REPORT_DEBUG_MODE': {
             'name': _('Debug Mode'),
             'description': _('Generate reports in debug mode (HTML output)'),
@@ -793,44 +802,6 @@ class InvenTreeSetting(BaseInvenTreeSetting):
             'default': 'PO',
         },
 
-        # enable/diable ui elements
-        'BUILD_FUNCTION_ENABLE': {
-            'name': _('Enable build'),
-            'description': _('Enable build functionality in InvenTree interface'),
-            'default': True,
-            'validator': bool,
-        },
-        'BUY_FUNCTION_ENABLE': {
-            'name': _('Enable buy'),
-            'description': _('Enable buy functionality in InvenTree interface'),
-            'default': True,
-            'validator': bool,
-        },
-        'SELL_FUNCTION_ENABLE': {
-            'name': _('Enable sell'),
-            'description': _('Enable sell functionality in InvenTree interface'),
-            'default': True,
-            'validator': bool,
-        },
-        'STOCK_FUNCTION_ENABLE': {
-            'name': _('Enable stock'),
-            'description': _('Enable stock functionality in InvenTree interface'),
-            'default': True,
-            'validator': bool,
-        },
-        'SO_FUNCTION_ENABLE': {
-            'name': _('Enable SO'),
-            'description': _('Enable SO functionality in InvenTree interface'),
-            'default': True,
-            'validator': bool,
-        },
-        'PO_FUNCTION_ENABLE': {
-            'name': _('Enable PO'),
-            'description': _('Enable PO functionality in InvenTree interface'),
-            'default': True,
-            'validator': bool,
-        },
-
         # login / SSO
         'LOGIN_ENABLE_PWD_FORGOT': {
             'name': _('Enable password forgot'),
diff --git a/InvenTree/common/test_views.py b/InvenTree/common/test_views.py
index 56a244ba0c..76a0a4516e 100644
--- a/InvenTree/common/test_views.py
+++ b/InvenTree/common/test_views.py
@@ -136,3 +136,24 @@ class SettingsViewTest(TestCase):
         for value in [False, 'False']:
             self.post(url, {'value': value}, valid=True)
             self.assertFalse(InvenTreeSetting.get_setting('PART_COMPONENT'))
+
+    def test_part_name_format(self):
+        """
+        Try posting some valid and invalid name formats for PART_NAME_FORMAT
+        """
+        setting = InvenTreeSetting.get_setting_object('PART_NAME_FORMAT')
+
+        # test default value
+        self.assertEqual(setting.value, "{{ part.IPN if part.IPN }}{{ ' | ' if part.IPN }}{{ part.name }}"
+                                        "{{ ' | ' if part.revision }}{{ part.revision if part.revision }}")
+
+        url = self.get_url(setting.pk)
+
+        # Try posting an invalid part name  format
+        invalid_values = ['{{asset.IPN}}', '{{part}}', '{{"|"}}', '{{part.falcon}}']
+        for invalid_value in invalid_values:
+            self.post(url, {'value': invalid_value}, valid=False)
+
+        # try posting valid value
+        new_format = "{{ part.name if part.name }} {{ ' with revision ' if part.revision }} {{ part.revision }}"
+        self.post(url, {'value': new_format}, valid=True)
diff --git a/InvenTree/company/templates/company/navbar.html b/InvenTree/company/templates/company/navbar.html
index 3c307704e6..b652d6b603 100644
--- a/InvenTree/company/templates/company/navbar.html
+++ b/InvenTree/company/templates/company/navbar.html
@@ -2,10 +2,6 @@
 {% load static %}
 {% load inventree_extras %}
 
-{% settings_value 'STOCK_FUNCTION_ENABLE' as enable_stock %}
-{% settings_value 'SO_FUNCTION_ENABLE' as enable_so %}
-{% settings_value 'PO_FUNCTION_ENABLE' as enable_po %}
-    
 <ul class='list-group'>
     <li class='list-group-item'>
         <a href='#' id='company-menu-toggle'>
@@ -32,7 +28,6 @@
     {% endif %}
 
     {% if company.is_manufacturer or company.is_supplier %}
-    {% if enable_stock %}
     <li class='list-group-item' title='{% trans "Stock Items" %}'>
         <a href='#' id='select-company-stock' class='nav-toggle'>
             <span class='fas fa-boxes sidebar-icon'></span>
@@ -40,9 +35,8 @@
         </a>
     </li>
     {% endif %}
-    {% endif %}
 
-    {% if company.is_supplier and enable_po %}
+    {% if company.is_supplier %}
     <li class='list-group-item' title='{% trans "Purchase Orders" %}'>
         <a href='#' id='select-purchase-orders' class='nav-toggle'>
             <span class='fas fa-shopping-cart sidebar-icon'></span>
@@ -51,7 +45,7 @@
     </li>
     {% endif %}
 
-    {% if company.is_customer and enable_so %}
+    {% if company.is_customer %}
     <li class='list-group-item' title='{% trans "Sales Orders" %}'>
         <a href='#' id='select-sales-orders' class='nav-toggle'>
             <span class='fas fa-truck sidebar-icon'></span>
diff --git a/InvenTree/order/admin.py b/InvenTree/order/admin.py
index 54e91ed844..25b0922291 100644
--- a/InvenTree/order/admin.py
+++ b/InvenTree/order/admin.py
@@ -20,6 +20,10 @@ class PurchaseOrderLineItemInlineAdmin(admin.StackedInline):
 
 class PurchaseOrderAdmin(ImportExportModelAdmin):
 
+    exclude = [
+        'reference_int',
+    ]
+
     list_display = (
         'reference',
         'supplier',
@@ -41,6 +45,10 @@ class PurchaseOrderAdmin(ImportExportModelAdmin):
 
 class SalesOrderAdmin(ImportExportModelAdmin):
 
+    exclude = [
+        'reference_int',
+    ]
+
     list_display = (
         'reference',
         'customer',
diff --git a/InvenTree/order/api.py b/InvenTree/order/api.py
index af30a3a5c5..df0ec1a5de 100644
--- a/InvenTree/order/api.py
+++ b/InvenTree/order/api.py
@@ -152,9 +152,13 @@ class POList(generics.ListCreateAPIView):
     filter_backends = [
         rest_filters.DjangoFilterBackend,
         filters.SearchFilter,
-        filters.OrderingFilter,
+        InvenTreeOrderingFilter,
     ]
 
+    ordering_field_aliases = {
+        'reference': ['reference_int', 'reference'],
+    }
+
     filter_fields = [
         'supplier',
     ]
@@ -504,9 +508,13 @@ class SOList(generics.ListCreateAPIView):
     filter_backends = [
         rest_filters.DjangoFilterBackend,
         filters.SearchFilter,
-        filters.OrderingFilter,
+        InvenTreeOrderingFilter,
     ]
 
+    ordering_field_aliases = {
+        'reference': ['reference_int', 'reference'],
+    }
+
     filter_fields = [
         'customer',
     ]
diff --git a/InvenTree/order/migrations/0051_auto_20211014_0623.py b/InvenTree/order/migrations/0051_auto_20211014_0623.py
new file mode 100644
index 0000000000..20cc893dd2
--- /dev/null
+++ b/InvenTree/order/migrations/0051_auto_20211014_0623.py
@@ -0,0 +1,23 @@
+# Generated by Django 3.2.5 on 2021-10-14 06:23
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('order', '0050_alter_purchaseorderlineitem_destination'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='purchaseorder',
+            name='reference_int',
+            field=models.IntegerField(default=0),
+        ),
+        migrations.AddField(
+            model_name='salesorder',
+            name='reference_int',
+            field=models.IntegerField(default=0),
+        ),
+    ]
diff --git a/InvenTree/order/migrations/0052_auto_20211014_0631.py b/InvenTree/order/migrations/0052_auto_20211014_0631.py
new file mode 100644
index 0000000000..b400437d20
--- /dev/null
+++ b/InvenTree/order/migrations/0052_auto_20211014_0631.py
@@ -0,0 +1,66 @@
+# Generated by Django 3.2.5 on 2021-10-14 06:31
+
+import re
+
+from django.db import migrations
+
+def build_refs(apps, schema_editor):
+    """
+    Rebuild the integer "reference fields" for existing Build objects
+    """
+
+    PurchaseOrder = apps.get_model('order', 'purchaseorder')
+
+    for order in PurchaseOrder.objects.all():
+
+        ref = 0
+
+        result = re.match(r"^(\d+)", order.reference)
+
+        if result and len(result.groups()) == 1:
+            try:
+                ref = int(result.groups()[0])
+            except:
+                ref = 0
+
+        order.reference_int = ref
+        order.save()
+
+    SalesOrder = apps.get_model('order', 'salesorder')
+
+    for order in SalesOrder.objects.all():
+
+        ref = 0
+
+        result = re.match(r"^(\d+)", order.reference)
+
+        if result and len(result.groups()) == 1:
+            try:
+                ref = int(result.groups()[0])
+            except:
+                ref = 0
+
+        order.reference_int = ref
+        order.save()
+
+
+def unbuild_refs(apps, schema_editor):
+    """
+    Provided only for reverse migration compatibility
+    """
+    pass
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('order', '0051_auto_20211014_0623'),
+    ]
+
+
+    operations = [
+        migrations.RunPython(
+            build_refs,
+            reverse_code=unbuild_refs
+        )
+    ]
diff --git a/InvenTree/order/models.py b/InvenTree/order/models.py
index 4ac8925259..0c45e3746a 100644
--- a/InvenTree/order/models.py
+++ b/InvenTree/order/models.py
@@ -28,7 +28,7 @@ from company.models import Company, SupplierPart
 from InvenTree.fields import InvenTreeModelMoneyField, RoundingDecimalField
 from InvenTree.helpers import decimal2string, increment, getSetting
 from InvenTree.status_codes import PurchaseOrderStatus, SalesOrderStatus, StockStatus, StockHistoryCode
-from InvenTree.models import InvenTreeAttachment
+from InvenTree.models import InvenTreeAttachment, ReferenceIndexingMixin
 
 
 def get_next_po_number():
@@ -89,7 +89,7 @@ def get_next_so_number():
     return reference
 
 
-class Order(models.Model):
+class Order(ReferenceIndexingMixin):
     """ Abstract model for an order.
 
     Instances of this class:
@@ -147,6 +147,9 @@ class Order(models.Model):
         return new_ref
 
     def save(self, *args, **kwargs):
+
+        self.rebuild_reference_field()
+
         if not self.creation_date:
             self.creation_date = datetime.now().date()
 
@@ -531,6 +534,12 @@ class SalesOrder(Order):
 
         return queryset
 
+    def save(self, *args, **kwargs):
+
+        self.rebuild_reference_field()
+
+        super().save(*args, **kwargs)
+
     def __str__(self):
 
         prefix = getSetting('SALESORDER_REFERENCE_PREFIX')
diff --git a/InvenTree/order/test_migrations.py b/InvenTree/order/test_migrations.py
new file mode 100644
index 0000000000..b7db1f1b70
--- /dev/null
+++ b/InvenTree/order/test_migrations.py
@@ -0,0 +1,59 @@
+"""
+Unit tests for the 'order' model data migrations
+"""
+
+from django_test_migrations.contrib.unittest_case import MigratorTestCase
+
+from InvenTree import helpers
+
+
+class TestForwardMigrations(MigratorTestCase):
+    """
+    Test entire schema migration
+    """
+
+    migrate_from = ('order', helpers.getOldestMigrationFile('order'))
+    migrate_to = ('order', helpers.getNewestMigrationFile('order'))
+
+    def prepare(self):
+        """
+        Create initial data set
+        """
+
+        # Create a purchase order from a supplier
+        Company = self.old_state.apps.get_model('company', 'company')
+
+        supplier = Company.objects.create(
+            name='Supplier A',
+            description='A great supplier!',
+            is_supplier=True
+        )
+
+        PurchaseOrder = self.old_state.apps.get_model('order', 'purchaseorder')
+
+        # Create some orders
+        for ii in range(10):
+
+            order = PurchaseOrder.objects.create(
+                supplier=supplier,
+                reference=f"{ii}-abcde",
+                description="Just a test order"
+            )
+
+            # Initially, the 'reference_int' field is unavailable
+            with self.assertRaises(AttributeError):
+                print(order.reference_int)
+
+    def test_ref_field(self):
+        """
+        Test that the 'reference_int' field has been created and is filled out correctly
+        """
+
+        PurchaseOrder = self.new_state.apps.get_model('order', 'purchaseorder')
+
+        for ii in range(10):
+
+            order = PurchaseOrder.objects.get(reference=f"{ii}-abcde")
+
+            # The integer reference field must have been correctly updated
+        self.assertEqual(order.reference_int, ii)
diff --git a/InvenTree/part/api.py b/InvenTree/part/api.py
index de37d4ea52..4dd9841332 100644
--- a/InvenTree/part/api.py
+++ b/InvenTree/part/api.py
@@ -27,7 +27,8 @@ from djmoney.contrib.exchange.exceptions import MissingRate
 
 from decimal import Decimal, InvalidOperation
 
-from .models import Part, PartCategory, BomItem
+from .models import Part, PartCategory
+from .models import BomItem, BomItemSubstitute
 from .models import PartParameter, PartParameterTemplate
 from .models import PartAttachment, PartTestTemplate
 from .models import PartSellPriceBreak, PartInternalPriceBreak
@@ -813,6 +814,27 @@ class PartList(generics.ListCreateAPIView):
             except (ValueError, Part.DoesNotExist):
                 pass
 
+        # Exclude specific part ID values?
+        exclude_id = []
+
+        for key in ['exclude_id', 'exclude_id[]']:
+            if key in params:
+                exclude_id += params.getlist(key, [])
+
+        if exclude_id:
+
+            id_values = []
+
+            for val in exclude_id:
+                try:
+                    # pk values must be integer castable
+                    val = int(val)
+                    id_values.append(val)
+                except ValueError:
+                    pass
+            
+            queryset = queryset.exclude(pk__in=id_values)
+
         # Exclude part variant tree?
         exclude_tree = params.get('exclude_tree', None)
 
@@ -1078,11 +1100,23 @@ class BomList(generics.ListCreateAPIView):
 
         queryset = self.filter_queryset(self.get_queryset())
 
-        serializer = self.get_serializer(queryset, many=True)
+        page = self.paginate_queryset(queryset)
+
+        if page is not None:
+            serializer = self.get_serializer(page, many=True)
+        else:
+            serializer = self.get_serializer(queryset, many=True)
 
         data = serializer.data
 
-        if request.is_ajax():
+        """
+        Determine the response type based on the request.
+        a) For HTTP requests (e.g. via the browseable API) return a DRF response
+        b) For AJAX requests, simply return a JSON rendered response.
+        """
+        if page is not None:
+            return self.get_paginated_response(data)
+        elif request.is_ajax():
             return JsonResponse(data, safe=False)
         else:
             return Response(data)
@@ -1102,7 +1136,7 @@ class BomList(generics.ListCreateAPIView):
 
         try:
             # Include or exclude pricing information in the serialized data
-            kwargs['include_pricing'] = str2bool(self.request.GET.get('include_pricing', True))
+            kwargs['include_pricing'] = self.include_pricing()
         except AttributeError:
             pass
 
@@ -1147,13 +1181,19 @@ class BomList(generics.ListCreateAPIView):
             except (ValueError, Part.DoesNotExist):
                 pass
 
-        include_pricing = str2bool(params.get('include_pricing', True))
-
-        if include_pricing:
+        if self.include_pricing():
             queryset = self.annotate_pricing(queryset)
 
         return queryset
     
+    def include_pricing(self):
+        """
+        Determine if pricing information should be included in the response
+        """
+        pricing_default = InvenTreeSetting.get_setting('PART_SHOW_PRICE_IN_BOM')
+
+        return str2bool(self.request.query_params.get('include_pricing', pricing_default))
+
     def annotate_pricing(self, queryset):
         """
         Add part pricing information to the queryset
@@ -1262,6 +1302,35 @@ class BomItemValidate(generics.UpdateAPIView):
         return Response(serializer.data)
 
 
+class BomItemSubstituteList(generics.ListCreateAPIView):
+    """
+    API endpoint for accessing a list of BomItemSubstitute objects
+    """
+
+    serializer_class = part_serializers.BomItemSubstituteSerializer
+    queryset = BomItemSubstitute.objects.all()
+    
+    filter_backends = [
+        DjangoFilterBackend,
+        filters.SearchFilter,
+        filters.OrderingFilter,
+    ]
+
+    filter_fields = [
+        'part',
+        'bom_item',
+    ]
+
+
+class BomItemSubstituteDetail(generics.RetrieveUpdateDestroyAPIView):
+    """
+    API endpoint for detail view of a single BomItemSubstitute object
+    """
+
+    queryset = BomItemSubstitute.objects.all()
+    serializer_class = part_serializers.BomItemSubstituteSerializer
+
+
 part_api_urls = [
     url(r'^tree/?', PartCategoryTree.as_view(), name='api-part-tree'),
 
@@ -1314,6 +1383,16 @@ part_api_urls = [
 ]
 
 bom_api_urls = [
+
+    url(r'^substitute/', include([
+
+        # Detail view
+        url(r'^(?P<pk>\d+)/', BomItemSubstituteDetail.as_view(), name='api-bom-substitute-detail'),
+
+        # Catch all
+        url(r'^.*$', BomItemSubstituteList.as_view(), name='api-bom-substitute-list'),
+    ])),
+
     # BOM Item Detail
     url(r'^(?P<pk>\d+)/', include([
         url(r'^validate/?', BomItemValidate.as_view(), name='api-bom-item-validate'),
diff --git a/InvenTree/part/migrations/0072_bomitemsubstitute.py b/InvenTree/part/migrations/0072_bomitemsubstitute.py
new file mode 100644
index 0000000000..2e48b10a8d
--- /dev/null
+++ b/InvenTree/part/migrations/0072_bomitemsubstitute.py
@@ -0,0 +1,22 @@
+# Generated by Django 3.2.5 on 2021-10-12 23:24
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('part', '0071_alter_partparametertemplate_name'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='BomItemSubstitute',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('bom_item', models.ForeignKey(help_text='Parent BOM item', on_delete=django.db.models.deletion.CASCADE, related_name='substitutes', to='part.bomitem', verbose_name='BOM Item')),
+                ('part', models.ForeignKey(help_text='Substitute part', limit_choices_to={'component': True}, on_delete=django.db.models.deletion.CASCADE, related_name='substitute_items', to='part.part', verbose_name='Part')),
+            ],
+        ),
+    ]
diff --git a/InvenTree/part/migrations/0073_auto_20211013_1048.py b/InvenTree/part/migrations/0073_auto_20211013_1048.py
new file mode 100644
index 0000000000..e581af603e
--- /dev/null
+++ b/InvenTree/part/migrations/0073_auto_20211013_1048.py
@@ -0,0 +1,21 @@
+# Generated by Django 3.2.5 on 2021-10-13 10:48
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('part', '0072_bomitemsubstitute'),
+    ]
+
+    operations = [
+        migrations.AlterModelOptions(
+            name='bomitemsubstitute',
+            options={'verbose_name': 'BOM Item Substitute'},
+        ),
+        migrations.AlterUniqueTogether(
+            name='bomitemsubstitute',
+            unique_together={('part', 'bom_item')},
+        ),
+    ]
diff --git a/InvenTree/part/models.py b/InvenTree/part/models.py
index 8c43a623a0..5cd9fa3180 100644
--- a/InvenTree/part/models.py
+++ b/InvenTree/part/models.py
@@ -23,6 +23,8 @@ from django.contrib.auth.models import User
 from django.db.models.signals import pre_delete
 from django.dispatch import receiver
 
+from jinja2 import Template
+
 from markdownx.models import MarkdownxField
 
 from django_cleanup import cleanup
@@ -38,6 +40,7 @@ from datetime import datetime
 import hashlib
 from djmoney.contrib.exchange.models import convert_money
 from common.settings import currency_code_default
+from common.models import InvenTreeSetting
 
 from InvenTree import helpers
 from InvenTree import validators
@@ -555,7 +558,9 @@ class Part(MPTTModel):
 
     @property
     def full_name(self):
-        """ Format a 'full name' for this Part.
+        """ Format a 'full name' for this Part based on the format PART_NAME_FORMAT defined in Inventree settings
+
+        As a failsafe option, the following is done
 
         - IPN (if not null)
         - Part name
@@ -564,17 +569,31 @@ class Part(MPTTModel):
         Elements are joined by the | character
         """
 
-        elements = []
+        full_name_pattern = InvenTreeSetting.get_setting('PART_NAME_FORMAT')
 
-        if self.IPN:
-            elements.append(self.IPN)
+        try:
+            context = {'part': self}
+            template_string = Template(full_name_pattern)
+            full_name = template_string.render(context)
 
-        elements.append(self.name)
+            return full_name
 
-        if self.revision:
-            elements.append(self.revision)
+        except AttributeError as attr_err:
 
-        return ' | '.join(elements)
+            logger.warning(f"exception while trying to create full name for part {self.name}", attr_err)
+
+            # Fallback to default format
+            elements = []
+
+            if self.IPN:
+                elements.append(self.IPN)
+
+            elements.append(self.name)
+
+            if self.revision:
+                elements.append(self.revision)
+
+            return ' | '.join(elements)
 
     def set_category(self, category):
 
@@ -2333,22 +2352,48 @@ class BomItem(models.Model):
     def get_api_url():
         return reverse('api-bom-list')
 
+    def get_valid_parts_for_allocation(self):
+        """
+        Return a list of valid parts which can be allocated against this BomItem:
+
+        - Include the referenced sub_part
+        - Include any directly specvified substitute parts
+        - If allow_variants is True, allow all variants of sub_part
+        """
+
+        # Set of parts we will allow
+        parts = set()
+
+        parts.add(self.sub_part)
+
+        # Variant parts (if allowed)
+        if self.allow_variants:
+            for variant in self.sub_part.get_descendants(include_self=False):
+                parts.add(variant)
+
+        # Substitute parts
+        for sub in self.substitutes.all():
+            parts.add(sub.part)
+
+        return parts
+
+    def is_stock_item_valid(self, stock_item):
+        """
+        Check if the provided StockItem object is "valid" for assignment against this BomItem
+        """
+
+        return stock_item.part in self.get_valid_parts_for_allocation()
+
     def get_stock_filter(self):
         """
         Return a queryset filter for selecting StockItems which match this BomItem
 
+        - Allow stock from all directly specified substitute parts
         - If allow_variants is True, allow all part variants
 
         """
 
-        # Target part
-        part = self.sub_part
-
-        if self.allow_variants:
-            variants = part.get_descendants(include_self=True)
-            return Q(part__in=[v.pk for v in variants])
-        else:
-            return Q(part=part)
+        return Q(part__in=[part.pk for part in self.get_valid_parts_for_allocation()])
 
     def save(self, *args, **kwargs):
 
@@ -2613,6 +2658,66 @@ class BomItem(models.Model):
         return "{pmin} to {pmax}".format(pmin=pmin, pmax=pmax)
 
 
+class BomItemSubstitute(models.Model):
+    """
+    A BomItemSubstitute provides a specification for alternative parts,
+    which can be used in a bill of materials.
+
+    Attributes:
+        bom_item: Link to the parent BomItem instance
+        part: The part which can be used as a substitute
+    """
+
+    class Meta:
+        verbose_name = _("BOM Item Substitute")
+
+        # Prevent duplication of substitute parts
+        unique_together = ('part', 'bom_item')
+
+    def save(self, *args, **kwargs):
+
+        self.full_clean()
+
+        super().save(*args, **kwargs)
+
+    def validate_unique(self, exclude=None):
+        """
+        Ensure that this BomItemSubstitute is "unique":
+
+        - It cannot point to the same "part" as the "sub_part" of the parent "bom_item"
+        """
+
+        super().validate_unique(exclude=exclude)
+
+        if self.part == self.bom_item.sub_part:
+            raise ValidationError({
+                "part": _("Substitute part cannot be the same as the master part"),
+            })
+
+    @staticmethod
+    def get_api_url():
+        return reverse('api-bom-substitute-list')
+
+    bom_item = models.ForeignKey(
+        BomItem,
+        on_delete=models.CASCADE,
+        related_name='substitutes',
+        verbose_name=_('BOM Item'),
+        help_text=_('Parent BOM item'),
+    )
+
+    part = models.ForeignKey(
+        Part,
+        on_delete=models.CASCADE,
+        related_name='substitute_items',
+        verbose_name=_('Part'),
+        help_text=_('Substitute part'),
+        limit_choices_to={
+            'component': True,
+        }
+    )
+
+
 class PartRelated(models.Model):
     """ Store and handle related parts (eg. mating connector, crimps, etc.) """
 
diff --git a/InvenTree/part/serializers.py b/InvenTree/part/serializers.py
index 509de43b68..869145e1af 100644
--- a/InvenTree/part/serializers.py
+++ b/InvenTree/part/serializers.py
@@ -23,7 +23,8 @@ from InvenTree.serializers import (InvenTreeAttachmentSerializerField,
 from InvenTree.status_codes import BuildStatus, PurchaseOrderStatus
 from stock.models import StockItem
 
-from .models import (BomItem, Part, PartAttachment, PartCategory,
+from .models import (BomItem, BomItemSubstitute,
+                     Part, PartAttachment, PartCategory,
                      PartParameter, PartParameterTemplate, PartSellPriceBreak,
                      PartStar, PartTestTemplate, PartCategoryParameterTemplate,
                      PartInternalPriceBreak)
@@ -388,8 +389,27 @@ class PartStarSerializer(InvenTreeModelSerializer):
         ]
 
 
+class BomItemSubstituteSerializer(InvenTreeModelSerializer):
+    """
+    Serializer for the BomItemSubstitute class
+    """
+
+    part_detail = PartBriefSerializer(source='part', read_only=True, many=False)
+
+    class Meta:
+        model = BomItemSubstitute
+        fields = [
+            'pk',
+            'bom_item',
+            'part',
+            'part_detail',
+        ]
+
+
 class BomItemSerializer(InvenTreeModelSerializer):
-    """ Serializer for BomItem object """
+    """
+    Serializer for BomItem object
+    """
 
     price_range = serializers.CharField(read_only=True)
 
@@ -397,6 +417,8 @@ class BomItemSerializer(InvenTreeModelSerializer):
 
     part = serializers.PrimaryKeyRelatedField(queryset=Part.objects.filter(assembly=True))
 
+    substitutes = BomItemSubstituteSerializer(many=True, read_only=True)
+
     part_detail = PartBriefSerializer(source='part', many=False, read_only=True)
 
     sub_part = serializers.PrimaryKeyRelatedField(queryset=Part.objects.filter(component=True))
@@ -515,6 +537,7 @@ class BomItemSerializer(InvenTreeModelSerializer):
             'reference',
             'sub_part',
             'sub_part_detail',
+            'substitutes',
             'price_range',
             'validated',
         ]
diff --git a/InvenTree/part/templates/part/bom.html b/InvenTree/part/templates/part/bom.html
index 750e205e04..988f65cfdb 100644
--- a/InvenTree/part/templates/part/bom.html
+++ b/InvenTree/part/templates/part/bom.html
@@ -1,11 +1,12 @@
 {% load i18n %}
 {% load inventree_extras %}
 
-{% if roles.part.change != True and editing_enabled %}
+{% if not roles.part.change %}
     <div class='alert alert-danger alert-block'>
         {% trans "You do not have permission to edit the BOM." %}
     </div>
-{% else %}
+{% endif %}
+
 {% if part.bom_checked_date %}
 {% if part.is_bom_valid %}
 <div class='alert alert-block alert-info'>
@@ -23,42 +24,38 @@
 
 <div id='bom-button-toolbar'>
     <div class="btn-group" role="group" aria-label="...">
-        {% if editing_enabled %}
-        <button class='btn btn-default' type='button' title='{% trans "Remove selected BOM items" %}' id='bom-item-delete'>
-            <span class='fas fa-trash-alt icon-red'></span>
-        </button>
-        <button class='btn btn-primary' type='button' title='{% trans "Import BOM data" %}' id='bom-upload'>
-            <span class='fas fa-file-upload'></span>
-        </button>
-        {% if part.variant_of %}
-        <button class='btn btn-default' type='button' title='{% trans "Copy BOM from parent part" %}' id='bom-duplicate'>
-            <span class='fas fa-clone'></span>
-        </button>
-        {% endif %}
-        <button class='btn btn-default' type='button' title='{% trans "New BOM Item" %}' id='bom-item-new'>
-            <span class='fas fa-plus-circle'></span>
-        </button>
-        <button class='btn btn-success' type='button' title='{% trans "Finish Editing" %}' id='editing-finished'>
-            <span class='fas fa-check-circle'></span>
-        </button>
-        {% elif part.active %}
+        <!-- Export menu -->
+        <div class='btn-group'>
+            <button id='export-options' title='{% trans "Export actions" %}' class='btn btn-default dropdown-toggle' type='button' data-toggle='dropdown'>
+                <span class='fas fa-download'></span> <span class='caret'></span>
+            </button>
+            <ul class='dropdown-menu' role='menu'>
+                <li><a href='#' id='download-bom'><span class='fas fa-file-download'></span> {% trans "Export BOM" %}</a></li>
+                <li><a href='#' id='print-bom-report'><span class='fas fa-file-pdf'></span> {% trans "Print BOM Report" %}</a></li>
+            </ul>
+        </div>
         {% if roles.part.change %}
-        <button class='btn btn-primary' type='button' title='{% trans "Edit BOM" %}' id='edit-bom'>
-            <span class='fas fa-edit'></span>
-        </button>
-        {% if part.is_bom_valid == False %}
-        <button class='btn btn-success' id='validate-bom' title='{% trans "Validate Bill of Materials" %}' type='button'>
-            <span class='fas fa-clipboard-check'></span>
+        <!-- Action menu -->
+        <div class='btn-group'>
+            <button id='bom-actions' title='{% trans "BOM actions" %}' class='btn btn-default dropdown-toggle' type='button' data-toggle='dropdown'>
+                <span class='fas fa-wrench'></span> <span class='caret'></span>
+            </button>
+            <ul class='dropdown-menu' role='menu'>
+                <li><a href='#' id='bom-upload'><span class='fas fa-file-upload'></span> {% trans "Upload BOM" %}</a></li>
+                {% if part.variant_of %}
+                <li><a href='#' id='bom-duplicate'><span class='fas fa-clone'></span> {% trans "Copy BOM" %}</a></li>
+                {% endif %}
+                {% if not part.is_bom_valid %}
+                <li><a href='#' id='validate-bom'><span class='fas fa-clipboard-check icon-green'></span> {% trans "Validate BOM" %}</a></li>
+                {% endif %}
+                <li><a href='#' id='bom-item-delete'><span class='fas fa-trash-alt icon-red'></span> {% trans "Delete Items" %}</a></li>
+            </ul>
+        </div>
+        <button class='btn btn-success' type='button' title='{% trans "New BOM Item" %}' id='bom-item-new'>
+            <span class='fas fa-plus-circle'></span> {% trans "Add BOM Item" %}
         </button>
         {% endif %}
-        {% endif %}
-        {% endif %}
-        <button title='{% trans "Export Bill of Materials" %}' class='btn btn-default' id='download-bom' type='button'>
-            <span class='fas fa-file-download'></span>
-        </button>
-        <button title='{% trans "Print BOM Report" %}' class='btn btn-default' id='print-bom-report' type='button'>
-            <span class='fas fa-file-pdf'></span>
-        </button>
+   
         <div class='filter-list' id='filter-list-bom'>
             <!-- Empty div (will be filled out with avilable BOM filters) -->
         </div>
@@ -67,4 +64,3 @@
 
 <table class='table table-bom table-condensed' data-toolbar="#bom-button-toolbar" id='bom-table'>
 </table>
-{% endif %}
\ No newline at end of file
diff --git a/InvenTree/part/templates/part/detail.html b/InvenTree/part/templates/part/detail.html
index 80762e437a..419ed74b1a 100644
--- a/InvenTree/part/templates/part/detail.html
+++ b/InvenTree/part/templates/part/detail.html
@@ -473,7 +473,11 @@
     onPanelLoad("bom", function() {
         // Load the BOM table data
         loadBomTable($("#bom-table"), {
-            editable: {{ editing_enabled }},
+            {% if roles.part.change %}
+            editable: true,
+            {% else %}
+            editable: false,
+            {% endif %}
             bom_url: "{% url 'api-bom-list' %}",
             part_url: "{% url 'api-part-list' %}",
             parent_id: {{ part.id }} ,
@@ -486,11 +490,6 @@
             ]
         );
 
-        {% if editing_enabled %}
-        $("#editing-finished").click(function() {
-            location.href = "{% url 'part-detail' part.id %}?display=bom";
-        });
-
         $('#bom-item-delete').click(function() {
 
             // Get a list of the selected BOM items
@@ -559,8 +558,6 @@
             });
         });
 
-        {% else %}
-
         $("#validate-bom").click(function() {
             launchModalForm(
                 "{% url 'bom-validate' part.id %}",
@@ -570,10 +567,6 @@
             );
         });
 
-        $("#edit-bom").click(function () {
-            location.href = "{% url 'part-detail' part.id %}?display=bom&edit=1";
-        });
-
         $("#download-bom").click(function () {
             launchModalForm("{% url 'bom-export' part.id %}",
                 {
@@ -584,8 +577,6 @@
             );
         });
 
-        {% endif %}
-
         $("#print-bom-report").click(function() {
             printBomReports([{{ part.pk }}]);
         });
@@ -629,10 +620,9 @@
         });
     });
 
-
     // Load the BOM table data in the pricing view
     loadBomTable($("#bom-pricing-table"), {
-        editable: {{ editing_enabled }},
+        editable: false,
         bom_url: "{% url 'api-bom-list' %}",
         part_url: "{% url 'api-part-list' %}",
         parent_id: {{ part.id }} ,
diff --git a/InvenTree/part/templates/part/navbar.html b/InvenTree/part/templates/part/navbar.html
index 139919d650..3ee444c3ba 100644
--- a/InvenTree/part/templates/part/navbar.html
+++ b/InvenTree/part/templates/part/navbar.html
@@ -4,12 +4,6 @@
 
 {% settings_value "PART_INTERNAL_PRICE" as show_internal_price %}
 {% settings_value 'PART_SHOW_RELATED' as show_related %}
-{% settings_value 'BUILD_FUNCTION_ENABLE' as enable_build %}
-{% settings_value 'STOCK_FUNCTION_ENABLE' as enable_stock %}
-{% settings_value 'PO_FUNCTION_ENABLE' as enable_po %}
-{% settings_value 'SO_FUNCTION_ENABLE' as enable_so %}
-{% settings_value 'BUY_FUNCTION_ENABLE' as enable_buy %}
-{% settings_value 'SELL_FUNCTION_ENABLE' as enable_sell %}
 
 <ul class='list-group'>
     <li class='list-group-item'>
@@ -31,14 +25,12 @@
         </a>
     </li>
     {% endif %}
-    {% if enable_stock %}
     <li class='list-group-item' title='{% trans "Stock Items" %}'>
         <a href='#' id='select-part-stock' class='nav-toggle'>
             <span class='menu-tab-icon fas fa-boxes sidebar-icon'></span>
             {% trans "Stock" %}
         </a>
     </li>
-    {% endif %}
     {% if part.assembly %}
     <li class='list-group-item' title='{% trans "Bill of Materials" %}'>
         <a href='#' id='select-bom' class='nav-toggle'>
@@ -46,7 +38,7 @@
             {% trans "Bill of Materials" %}
         </a>
     </li>
-    {% if roles.build.view and enable_build %}
+    {% if roles.build.view %}
     <li class='list-group-item ' title='{% trans "Build Orders" %}'>
         <a href='#' id='select-build-orders' class='nav-toggle'>
             <span class='menu-tab-icon fas fa-tools sidebar-icon'></span>
@@ -63,22 +55,19 @@
         </a>
     </li>
     {% endif %}
-    {% if enable_buy or enable_sell %}
     <li class='list-group-item' title='{% trans "Pricing Information" %}'>
         <a href='#' id='select-pricing' class='nav-toggle'>
             <span class='menu-tab-icon fas fa-dollar-sign sidebar-icon'></span>
             {% trans "Prices" %}
         </a>
     </li>
-    {% endif %}
-    {% if part.purchaseable and roles.purchase_order.view and enable_buy %}
+    {% if part.purchaseable and roles.purchase_order.view %}
     <li class='list-group-item' title='{% trans "Suppliers" %}'>
         <a href='#' id='select-suppliers' class='nav-toggle'>
             <span class='menu-tab-icon fas fa-building sidebar-icon'></span>
             {% trans "Suppliers" %}
         </a>
     </li>
-    {% if enable_po %}
     <li class='list-group-item' title='{% trans "Purchase Orders" %}'>
         <a href='#' id='select-purchase-orders' class='nav-toggle'>
             <span class='menu-tab-icon fas fa-shopping-cart sidebar-icon'></span>
@@ -86,8 +75,7 @@
         </a>
     </li>
     {% endif %}
-    {% endif %}
-    {% if part.salable and roles.sales_order.view and enable_sell and enable_so %}
+    {% if part.salable and roles.sales_order.view %}
     <li class='list-group-item' title='{% trans "Sales Orders" %}'>
         <a href='#' id='select-sales-orders' class='nav-toggle'>
             <span class='menu-tab-icon fas fa-truck sidebar-icon'></span>
diff --git a/InvenTree/part/templates/part/part_base.html b/InvenTree/part/templates/part/part_base.html
index c1542ac13b..2d27283830 100644
--- a/InvenTree/part/templates/part/part_base.html
+++ b/InvenTree/part/templates/part/part_base.html
@@ -10,11 +10,6 @@
 
 {% block content %}
 
-{% settings_value 'BUY_FUNCTION_ENABLE' as enable_buy %}
-{% settings_value 'SELL_FUNCTION_ENABLE' as enable_sell %}
-{% settings_value 'PO_FUNCTION_ENABLE' as enable_po %}
-{% settings_value 'STOCK_FUNCTION_ENABLE' as enable_stock %}
-
 <div class="panel panel-default panel-inventree">
     <!-- Default panel contents -->
     <div class="panel-heading"><h3>{{ part.full_name }}</h3></div>
@@ -85,12 +80,10 @@
                     </div>
                     {% endif %}
                     {% if part.active %}
-                    {% if enable_buy or enable_sell  %}
                     <button type='button' class='btn btn-default' id='price-button' title='{% trans "Show pricing information" %}'>
                         <span id='part-price-icon' class='fas fa-dollar-sign'/>
                     </button>
-                    {% endif %}
-                    {% if roles.stock.change and enable_stock %}
+                    {% if roles.stock.change %}
                     <div class='btn-group'>
                         <button id='stock-actions' title='{% trans "Stock actions" %}' class='btn btn-default dropdown-toggle' type='button' data-toggle='dropdown'>
                             <span class='fas fa-boxes'></span> <span class='caret'></span>
@@ -112,13 +105,11 @@
                     </div>
                     {% endif %}
                     {% if part.purchaseable and roles.purchase_order.add %}
-                    {% if enable_buy and enable_po %}
                     <button type='button' class='btn btn-default' id='part-order' title='{% trans "Order part" %}'>
                         <span id='part-order-icon' class='fas fa-shopping-cart'/>
                     </button>
                     {% endif %}
                     {% endif %}
-                    {% endif %}
                     <!-- Part actions -->
                     {% if roles.part.add or roles.part.change or roles.part.delete %}
                     <div class='btn-group'>
diff --git a/InvenTree/part/test_api.py b/InvenTree/part/test_api.py
index ac9d6bdf45..ec377bd513 100644
--- a/InvenTree/part/test_api.py
+++ b/InvenTree/part/test_api.py
@@ -1,4 +1,5 @@
 # -*- coding: utf-8 -*-
+from __future__ import unicode_literals
 
 import PIL
 
@@ -11,7 +12,8 @@ from InvenTree.api_tester import InvenTreeAPITestCase
 from InvenTree.status_codes import StockStatus
 
 from part.models import Part, PartCategory
-from stock.models import StockItem
+from part.models import BomItem, BomItemSubstitute
+from stock.models import StockItem, StockLocation
 from company.models import Company
 from common.models import InvenTreeSetting
 
@@ -273,53 +275,6 @@ class PartAPITest(InvenTreeAPITestCase):
         self.assertEqual(response.status_code, status.HTTP_200_OK)
         self.assertEqual(len(response.data), 3)
 
-    def test_get_bom_list(self):
-        """ There should be 4 BomItem objects in the database """
-        url = reverse('api-bom-list')
-        response = self.client.get(url, format='json')
-        self.assertEqual(len(response.data), 5)
-
-    def test_get_bom_detail(self):
-        # Get the detail for a single BomItem
-        url = reverse('api-bom-item-detail', kwargs={'pk': 3})
-        response = self.client.get(url, format='json')
-        self.assertEqual(response.status_code, status.HTTP_200_OK)
-        self.assertEqual(int(float(response.data['quantity'])), 25)
-
-        # Increase the quantity
-        data = response.data
-        data['quantity'] = 57
-        data['note'] = 'Added a note'
-
-        response = self.client.patch(url, data, format='json')
-
-        # Check that the quantity was increased and a note added
-        self.assertEqual(response.status_code, status.HTTP_200_OK)
-        self.assertEqual(int(float(response.data['quantity'])), 57)
-        self.assertEqual(response.data['note'], 'Added a note')
-
-    def test_add_bom_item(self):
-        url = reverse('api-bom-list')
-
-        data = {
-            'part': 100,
-            'sub_part': 4,
-            'quantity': 777,
-        }
-
-        response = self.client.post(url, data, format='json')
-        self.assertEqual(response.status_code, status.HTTP_201_CREATED)
-
-        # Now try to create a BomItem which points to a non-assembly part (should fail)
-        data['part'] = 3
-        response = self.client.post(url, data, format='json')
-        self.assertEqual(response.status_code, status.HTTP_400_BAD_REQUEST)
-
-        # TODO - Now try to create a BomItem which references itself
-        data['part'] = 2
-        data['sub_part'] = 2
-        response = self.client.post(url, data, format='json')
-
     def test_test_templates(self):
 
         url = reverse('api-part-test-template-list')
@@ -926,6 +881,249 @@ class PartAPIAggregationTest(InvenTreeAPITestCase):
         self.assertEqual(data['stock_item_count'], 105)
 
 
+class BomItemTest(InvenTreeAPITestCase):
+    """
+    Unit tests for the BomItem API
+    """
+
+    fixtures = [
+        'category',
+        'part',
+        'location',
+        'stock',
+        'bom',
+        'company',
+    ]
+
+    roles = [
+        'part.add',
+        'part.change',
+        'part.delete',
+    ]
+
+    def setUp(self):
+        super().setUp()
+
+    def test_bom_list(self):
+        """
+        Tests for the BomItem list endpoint
+        """
+
+        # How many BOM items currently exist in the database?
+        n = BomItem.objects.count()
+        
+        url = reverse('api-bom-list')
+        response = self.get(url, expected_code=200)
+        self.assertEqual(len(response.data), n)
+
+        # Now, filter by part
+        response = self.get(
+            url,
+            data={
+                'part': 100,
+            },
+            expected_code=200
+        )
+
+        print("results:", len(response.data))
+
+    def test_get_bom_detail(self):
+        """
+        Get the detail view for a single BomItem object
+        """
+
+        url = reverse('api-bom-item-detail', kwargs={'pk': 3})
+
+        response = self.get(url, expected_code=200)
+
+        self.assertEqual(int(float(response.data['quantity'])), 25)
+
+        # Increase the quantity
+        data = response.data
+        data['quantity'] = 57
+        data['note'] = 'Added a note'
+
+        response = self.patch(url, data, expected_code=200)
+
+        self.assertEqual(int(float(response.data['quantity'])), 57)
+        self.assertEqual(response.data['note'], 'Added a note')
+
+    def test_add_bom_item(self):
+        """
+        Test that we can create a new BomItem via the API
+        """
+
+        url = reverse('api-bom-list')
+
+        data = {
+            'part': 100,
+            'sub_part': 4,
+            'quantity': 777,
+        }
+
+        self.post(url, data, expected_code=201)
+        
+        # Now try to create a BomItem which references itself
+        data['part'] = 100
+        data['sub_part'] = 100
+        self.client.post(url, data, expected_code=400)
+
+    def test_variants(self):
+        """
+        Tests for BomItem use with variants
+        """
+
+        stock_url = reverse('api-stock-list')
+
+        # BOM item we are interested in
+        bom_item = BomItem.objects.get(pk=1)
+
+        bom_item.allow_variants = True
+        bom_item.save()
+
+        # sub part that the BOM item points to
+        sub_part = bom_item.sub_part
+
+        sub_part.is_template = True
+        sub_part.save()
+
+        # How many stock items are initially available for this part?
+        response = self.get(
+            stock_url,
+            {
+                'bom_item': bom_item.pk,
+            },
+            expected_code=200
+        )
+
+        n_items = len(response.data)
+        self.assertEqual(n_items, 2)
+
+        loc = StockLocation.objects.get(pk=1)
+
+        # Now we will create some variant parts and stock
+        for ii in range(5):
+            
+            # Create a variant part!
+            variant = Part.objects.create(
+                name=f"Variant_{ii}",
+                description="A variant part",
+                component=True,
+                variant_of=sub_part
+            )
+
+            variant.save()
+
+            Part.objects.rebuild()
+
+            # Create some stock items for this new part
+            for jj in range(ii):
+                StockItem.objects.create(
+                    part=variant,
+                    location=loc,
+                    quantity=100
+                )
+
+            # Keep track of running total
+            n_items += ii
+
+            # Now, there should be more stock items available!
+            response = self.get(
+                stock_url,
+                {
+                    'bom_item': bom_item.pk,
+                },
+                expected_code=200
+            )
+
+            self.assertEqual(len(response.data), n_items)
+
+        # Now, disallow variant parts in the BomItem
+        bom_item.allow_variants = False
+        bom_item.save()
+
+        # There should now only be 2 stock items available again
+        response = self.get(
+            stock_url,
+            {
+                'bom_item': bom_item.pk,
+            },
+            expected_code=200
+        )
+
+        self.assertEqual(len(response.data), 2)
+
+    def test_substitutes(self):
+        """
+        Tests for BomItem substitutes
+        """
+
+        url = reverse('api-bom-substitute-list')
+        stock_url = reverse('api-stock-list')
+
+        # Initially we have no substitute parts
+        response = self.get(url, expected_code=200)
+        self.assertEqual(len(response.data), 0)
+
+        # BOM item we are interested in
+        bom_item = BomItem.objects.get(pk=1)
+
+        # Filter stock items which can be assigned against this stock item
+        response = self.get(
+            stock_url,
+            {
+                "bom_item": bom_item.pk,
+            },
+            expected_code=200
+        )
+
+        n_items = len(response.data)
+
+        loc = StockLocation.objects.get(pk=1)
+
+        # Let's make some!
+        for ii in range(5):
+            sub_part = Part.objects.create(
+                name=f"Substitute {ii}",
+                description="A substitute part",
+                component=True,
+                is_template=False,
+                assembly=False
+            )
+
+            # Create a new StockItem for this Part
+            StockItem.objects.create(
+                part=sub_part,
+                quantity=1000,
+                location=loc,
+            )
+
+            # Now, create an "alternative" for the BOM Item
+            BomItemSubstitute.objects.create(
+                bom_item=bom_item,
+                part=sub_part
+            )
+
+            # We should be able to filter the API list to just return this new part
+            response = self.get(url, data={'part': sub_part.pk}, expected_code=200)
+            self.assertEqual(len(response.data), 1)
+
+            # We should also have more stock available to allocate against this BOM item!
+            response = self.get(
+                stock_url,
+                {
+                    "bom_item": bom_item.pk,
+                },
+                expected_code=200
+            )
+
+            self.assertEqual(len(response.data), n_items + ii + 1)
+
+        # There should now be 5 substitute parts available in the database
+        response = self.get(url, expected_code=200)
+        self.assertEqual(len(response.data), 5)
+
+
 class PartParameterTest(InvenTreeAPITestCase):
     """
     Tests for the ParParameter API
diff --git a/InvenTree/part/test_bom_item.py b/InvenTree/part/test_bom_item.py
index be9740d128..cd3c77845c 100644
--- a/InvenTree/part/test_bom_item.py
+++ b/InvenTree/part/test_bom_item.py
@@ -1,8 +1,13 @@
+# -*- coding: utf-8 -*-
+
+from __future__ import unicode_literals
+from django.db import transaction
+
 from django.test import TestCase
 import django.core.exceptions as django_exceptions
 from decimal import Decimal
 
-from .models import Part, BomItem
+from .models import Part, BomItem, BomItemSubstitute
 
 
 class BomItemTest(TestCase):
@@ -130,3 +135,67 @@ class BomItemTest(TestCase):
             self.bob.get_bom_price_range(1, internal=True),
             (Decimal(27.5), Decimal(87.5))
         )
+
+    def test_substitutes(self):
+        """
+        Tests for BOM item substitutes
+        """
+
+        # We will make some subtitute parts for the "orphan" part
+        bom_item = BomItem.objects.get(
+            part=self.bob,
+            sub_part=self.orphan
+        )
+
+        # No substitute parts available
+        self.assertEqual(bom_item.substitutes.count(), 0)
+
+        subs = []
+
+        for ii in range(5):
+            
+            # Create a new part
+            sub_part = Part.objects.create(
+                name=f"Orphan {ii}",
+                description="A substitute part for the orphan part",
+                component=True,
+                is_template=False,
+                assembly=False,
+            )
+
+            subs.append(sub_part)
+
+            # Link it as a substitute part
+            BomItemSubstitute.objects.create(
+                bom_item=bom_item,
+                part=sub_part
+            )
+
+            # Try to link it again (this should fail as it is a duplicate substitute)
+            with self.assertRaises(django_exceptions.ValidationError):
+                with transaction.atomic():
+                    BomItemSubstitute.objects.create(
+                        bom_item=bom_item,
+                        part=sub_part
+                    )
+
+        # There should be now 5 substitute parts available
+        self.assertEqual(bom_item.substitutes.count(), 5)
+            
+        # Try to create a substitute which points to the same sub-part (should fail)
+        with self.assertRaises(django_exceptions.ValidationError):
+            BomItemSubstitute.objects.create(
+                bom_item=bom_item,
+                part=self.orphan,
+            )
+
+        # Remove one substitute part
+        bom_item.substitutes.last().delete()
+
+        self.assertEqual(bom_item.substitutes.count(), 4)
+
+        for sub in subs:
+            sub.delete()
+
+        # The substitution links should have been automatically removed
+        self.assertEqual(bom_item.substitutes.count(), 0)
diff --git a/InvenTree/part/test_views.py b/InvenTree/part/test_views.py
index 5f2a9b1583..2995d45811 100644
--- a/InvenTree/part/test_views.py
+++ b/InvenTree/part/test_views.py
@@ -87,16 +87,6 @@ class PartDetailTest(PartViewTestCase):
         self.assertEqual(response.context['part'].pk, pk)
         self.assertEqual(response.context['category'], part.category)
 
-        self.assertFalse(response.context['editing_enabled'])
-
-    def test_editable(self):
-
-        pk = 1
-        response = self.client.get(reverse('part-detail', args=(pk,)), {'edit': True})
-
-        self.assertEqual(response.status_code, 200)
-        self.assertTrue(response.context['editing_enabled'])
-
     def test_part_detail_from_ipn(self):
         """
         Test that we can retrieve a part detail page from part IPN:
diff --git a/InvenTree/part/views.py b/InvenTree/part/views.py
index ee8699dfea..5a4167ea05 100644
--- a/InvenTree/part/views.py
+++ b/InvenTree/part/views.py
@@ -404,20 +404,13 @@ class PartDetail(InvenTreeRoleMixin, DetailView):
 
     # Add in some extra context information based on query params
     def get_context_data(self, **kwargs):
-        """ Provide extra context data to template
-
-        - If '?editing=True', set 'editing_enabled' context variable
+        """
+        Provide extra context data to template
         """
         context = super().get_context_data(**kwargs)
 
         part = self.get_object()
 
-        if str2bool(self.request.GET.get('edit', '')):
-            # Allow BOM editing if the part is active
-            context['editing_enabled'] = 1 if part.active else 0
-        else:
-            context['editing_enabled'] = 0
-
         ctx = part.get_context_data(self.request)
         context.update(**ctx)
 
diff --git a/InvenTree/stock/templates/stock/item_base.html b/InvenTree/stock/templates/stock/item_base.html
index 798802ab81..b7019ff887 100644
--- a/InvenTree/stock/templates/stock/item_base.html
+++ b/InvenTree/stock/templates/stock/item_base.html
@@ -72,7 +72,9 @@
     {% if barcodes %}
     <!-- Barcode actions menu -->
     <div class='btn-group'>
-        <button id='barcode-options' title='{% trans "Barcode actions" %}' class='btn btn-default dropdown-toggle' type='button' data-toggle='dropdown'><span class='fas fa-qrcode'></span> <span class='caret'></span></button>
+        <button id='barcode-options' title='{% trans "Barcode actions" %}' class='btn btn-default dropdown-toggle' type='button' data-toggle='dropdown'>
+            <span class='fas fa-qrcode'></span> <span class='caret'></span>
+        </button>
         <ul class='dropdown-menu' role='menu'>
             <li><a href='#' id='show-qr-code'><span class='fas fa-qrcode'></span> {% trans "Show QR Code" %}</a></li>
             {% if roles.stock.change %}
diff --git a/InvenTree/templates/InvenTree/settings/build.html b/InvenTree/templates/InvenTree/settings/build.html
index 897c624a38..6d16512a99 100644
--- a/InvenTree/templates/InvenTree/settings/build.html
+++ b/InvenTree/templates/InvenTree/settings/build.html
@@ -13,8 +13,6 @@
 <table class='table table-striped table-condensed'>
     {% include "InvenTree/settings/header.html" %}
     <tbody>
-        {% include "InvenTree/settings/setting.html" with key="BUILD_FUNCTION_ENABLE" icon="fa-check" %}
-        <tr><td colspan='5'></td></tr>
         {% include "InvenTree/settings/setting.html" with key="BUILDORDER_REFERENCE_PREFIX" %}
         {% include "InvenTree/settings/setting.html" with key="BUILDORDER_REFERENCE_REGEX" %}
     </tbody>
diff --git a/InvenTree/templates/InvenTree/settings/part.html b/InvenTree/templates/InvenTree/settings/part.html
index 0ec5f56db6..ddd6fae1a9 100644
--- a/InvenTree/templates/InvenTree/settings/part.html
+++ b/InvenTree/templates/InvenTree/settings/part.html
@@ -17,6 +17,7 @@
         {% include "InvenTree/settings/setting.html" with key="PART_IPN_REGEX" %}
         {% include "InvenTree/settings/setting.html" with key="PART_ALLOW_DUPLICATE_IPN" %}
         {% include "InvenTree/settings/setting.html" with key="PART_ALLOW_EDIT_IPN" %}
+        {% include "InvenTree/settings/setting.html" with key="PART_NAME_FORMAT" %}
         {% include "InvenTree/settings/setting.html" with key="PART_SHOW_PRICE_IN_FORMS" icon="fa-dollar-sign" %}
         {% include "InvenTree/settings/setting.html" with key="PART_SHOW_PRICE_IN_BOM" icon="fa-dollar-sign" %}
         {% include "InvenTree/settings/setting.html" with key="PART_SHOW_RELATED" icon="fa-random" %}
diff --git a/InvenTree/templates/InvenTree/settings/po.html b/InvenTree/templates/InvenTree/settings/po.html
index e5d55f227b..f8a114bb12 100644
--- a/InvenTree/templates/InvenTree/settings/po.html
+++ b/InvenTree/templates/InvenTree/settings/po.html
@@ -11,9 +11,6 @@
 <table class='table table-striped table-condensed'>
     {% include "InvenTree/settings/header.html" %}
     <tbody>
-        {% include "InvenTree/settings/setting.html" with key="PO_FUNCTION_ENABLE" icon="fa-check" %}
-        {% include "InvenTree/settings/setting.html" with key="BUY_FUNCTION_ENABLE" icon="fa-check" %}
-        <tr><td colspan='5'></td></tr>
         {% include "InvenTree/settings/setting.html" with key="PURCHASEORDER_REFERENCE_PREFIX" %}
     </tbody>
 </table>
diff --git a/InvenTree/templates/InvenTree/settings/so.html b/InvenTree/templates/InvenTree/settings/so.html
index 48a88e3aad..2fe5680d71 100644
--- a/InvenTree/templates/InvenTree/settings/so.html
+++ b/InvenTree/templates/InvenTree/settings/so.html
@@ -12,9 +12,6 @@
 <table class='table table-striped table-condensed'>
     {% include "InvenTree/settings/header.html" %}
     <tbody>
-        {% include "InvenTree/settings/setting.html" with key="SO_FUNCTION_ENABLE" icon="fa-check" %}
-        {% include "InvenTree/settings/setting.html" with key="SELL_FUNCTION_ENABLE" icon="fa-check" %}
-        <tr><td colspan='5'></td></tr>
         {% include "InvenTree/settings/setting.html" with key="SALESORDER_REFERENCE_PREFIX" %}
     </tbody>
 </table>
diff --git a/InvenTree/templates/InvenTree/settings/stock.html b/InvenTree/templates/InvenTree/settings/stock.html
index bdd417b56e..e05def09a6 100644
--- a/InvenTree/templates/InvenTree/settings/stock.html
+++ b/InvenTree/templates/InvenTree/settings/stock.html
@@ -12,8 +12,6 @@
 <table class='table table-striped table-condensed'>
     {% include "InvenTree/settings/header.html" %}
     <tbody>
-        {% include "InvenTree/settings/setting.html" with key="STOCK_FUNCTION_ENABLE" icon="fa-check" %}
-        <tr><td colspan='5'></td></tr>
         {% include "InvenTree/settings/setting.html" with key="STOCK_GROUP_BY_PART" icon="fa-layer-group" %}
         {% include "InvenTree/settings/setting.html" with key="STOCK_ENABLE_EXPIRY" icon="fa-stopwatch" %}
         {% include "InvenTree/settings/setting.html" with key="STOCK_STALE_DAYS" icon="fa-calendar" %}
diff --git a/InvenTree/templates/js/translated/bom.js b/InvenTree/templates/js/translated/bom.js
index 3524bc5c40..89ae428bcd 100644
--- a/InvenTree/templates/js/translated/bom.js
+++ b/InvenTree/templates/js/translated/bom.js
@@ -143,6 +143,174 @@ function newPartFromBomWizard(e) {
 }
 
 
+/*
+ * Launch a modal dialog displaying the "substitute parts" for a particular BomItem
+ *
+ * If editable, allows substitutes to be added and deleted
+ */
+function bomSubstitutesDialog(bom_item_id, substitutes, options={}) {
+
+    // Reload data for the parent table
+    function reloadParentTable() {
+        if (options.table) {
+            options.table.bootstrapTable('refresh');
+        }
+    }
+
+    // Extract a list of all existing "substitute" id values
+    function getSubstituteIdValues(modal) {
+
+        var id_values = [];
+
+        $(modal).find('.substitute-row').each(function(el) {
+            var part = $(this).attr('part');
+            id_values.push(part);
+        });
+
+        return id_values;
+    }
+
+    function renderSubstituteRow(substitute) {
+
+        var pk = substitute.pk;
+
+        var part = substitute.part_detail;
+
+        var thumb = thumbnailImage(part.thumbnail || part.image);
+
+        var buttons = '';
+
+        buttons += makeIconButton('fa-times icon-red', 'button-row-remove', pk, '{% trans "Remove substitute part" %}');
+
+        // Render a single row
+        var html = `
+        <tr id='substitute-row-${pk}' class='substitute-row' part='${substitute.part}'>
+            <td id='part-${pk}'>
+                <a href='/part/${part.pk}/'>
+                    ${thumb} ${part.full_name}
+                </a>
+            </td>
+            <td id='description-${pk}'><em>${part.description}</em></td>
+            <td>${buttons}</td>
+        </tr>
+        `;
+
+        return html;
+    }
+
+    // Construct a table to render the rows
+    var rows = '';
+
+    substitutes.forEach(function(sub) {
+        rows += renderSubstituteRow(sub);
+    });
+
+    var html = `
+    <table class='table table-striped table-condensed' id='substitute-table'>
+        <thead>
+            <tr>
+                <th>{% trans "Part" %}</th>
+                <th>{% trans "Description" %}</th>
+                <th><!-- Actions --></th>
+            </tr>
+        </thead>
+        <tbody>
+            ${rows}
+        </tbody>
+    </table>
+    `;
+
+    html += `
+    <div class='alert alert-success alert-block'>
+        {% trans "Select and add a new variant item using the input below" %}
+    </div>
+    `;
+
+    // Add a callback to remove a row from the table
+    function addRemoveCallback(modal, element) {
+        $(modal).find(element).click(function() {
+            var pk = $(this).attr('pk');
+
+            var pre = `
+            <div class='alert alert-block alert-warning'>
+            {% trans "Are you sure you wish to remove this substitute part link?" %}
+            </div>
+            `;
+
+            constructForm(`/api/bom/substitute/${pk}/`, {
+                method: 'DELETE',
+                title: '{% trans "Remove Substitute Part" %}',
+                preFormContent: pre,
+                confirm: true,
+                onSuccess: function() {
+                    $(modal).find(`#substitute-row-${pk}`).remove();
+                    reloadParentTable();
+                }
+            });
+        });
+    }
+
+    constructForm('{% url "api-bom-substitute-list" %}', {
+        method: 'POST',
+        fields: {
+            bom_item: {
+                hidden: true,
+                value: bom_item_id,
+            },
+            part: {
+                required: false,
+                adjustFilters: function(query, opts) {
+
+                    var subs = getSubstituteIdValues(opts.modal);
+
+                    // Also exclude the "master" part (if provided)
+                    if (options.sub_part) {
+                        subs.push(options.sub_part);
+                    }
+
+                    if (subs.length > 0) {
+                        query.exclude_id = subs;
+                    }
+
+                    return query;
+                }
+            },
+        },
+        preFormContent: html,
+        cancelText: '{% trans "Close" %}',
+        submitText: '{% trans "Add Substitute" %}',
+        title: '{% trans "Edit BOM Item Substitutes" %}',
+        afterRender: function(fields, opts) {
+            addRemoveCallback(opts.modal, '.button-row-remove');
+        },
+        preventClose: true,
+        onSuccess: function(response, opts) {
+
+            // Clear the form
+            var field = {
+                type: 'related field',
+            };
+
+            updateFieldValue('part', null, field, opts);
+
+            // Add the new substitute to the table
+            var row = renderSubstituteRow(response);
+            $(opts.modal).find('#substitute-table > tbody:last-child').append(row);
+
+            // Add a callback to the new button
+            addRemoveCallback(opts.modal, `#button-row-remove-${response.pk}`);
+
+            // Re-enable the "submit" button
+            $(opts.modal).find('#modal-form-submit').prop('disabled', false);
+            
+            // Reload the parent BOM table
+            reloadParentTable();
+        }
+    });
+
+}
+
+
 function loadBomTable(table, options) {
     /* Load a BOM table with some configurable options.
      * 
@@ -229,6 +397,14 @@ function loadBomTable(table, options) {
 
                 html += makePartIcons(row.sub_part_detail);
 
+                if (row.substitutes && row.substitutes.length > 0) {
+                    html += makeIconBadge('fa-exchange-alt', '{% trans "Substitutes Available" %}');
+                }
+
+                if (row.allow_variants) {
+                    html += makeIconBadge('fa-sitemap', '{% trans "Variant stock allowed" %}');
+                }
+
                 // Display an extra icon if this part is an assembly
                 if (sub_part.assembly) {
                     var text = `<span title='{% trans "Open subassembly" %}' class='fas fa-stream label-right'></span>`;
@@ -300,6 +476,20 @@ function loadBomTable(table, options) {
             return renderLink(text, url);
         }
     });
+
+    cols.push({
+        field: 'substitutes',
+        title: '{% trans "Substitutes" %}',
+        searchable: false,
+        sortable: true,
+        formatter: function(value, row) {
+            if (row.substitutes && row.substitutes.length > 0) {
+                return row.substitutes.length;
+            } else {
+                return `-`;
+            }
+        }
+    });
     
     if (show_pricing) {
         cols.push({
@@ -420,18 +610,17 @@ function loadBomTable(table, options) {
 
                 if (row.part == options.parent_id) {
 
-                    var bValidate = `<button title='{% trans "Validate BOM Item" %}' class='bom-validate-button btn btn-default btn-glyph' type='button' pk='${row.pk}'><span class='fas fa-check-circle icon-blue'/></button>`;
+                    var bValidate = makeIconButton('fa-check-circle icon-green', 'bom-validate-button', row.pk, '{% trans "Validate BOM Item" %}');
 
                     var bValid = `<span title='{% trans "This line has been validated" %}' class='fas fa-check-double icon-green'/>`;
 
-                    var bEdit = `<button title='{% trans "Edit BOM Item" %}' class='bom-edit-button btn btn-default btn-glyph' type='button' pk='${row.pk}'><span class='fas fa-edit'></span></button>`;
+                    var bSubs = makeIconButton('fa-exchange-alt icon-blue', 'bom-substitutes-button', row.pk, '{% trans "Edit substitute parts" %}');
 
-                    var bDelt = `<button title='{% trans "Delete BOM Item" %}' class='bom-delete-button btn btn-default btn-glyph' type='button' pk='${row.pk}'><span class='fas fa-trash-alt icon-red'></span></button>`;
+                    var bEdit = makeIconButton('fa-edit icon-blue', 'bom-edit-button', row.pk, '{% trans "Edit BOM Item" %}');
 
-                    var html = `<div class='btn-group' role='group'>`;
+                    var bDelt = makeIconButton('fa-trash-alt icon-red', 'bom-delete-button', row.pk, '{% trans "Delete BOM Item" %}');
 
-                    html += bEdit;
-                    html += bDelt;
+                    var html = `<div class='btn-group float-right' role='group' style='min-width: 100px;'>`;
 
                     if (!row.validated) {
                         html += bValidate;
@@ -439,6 +628,10 @@ function loadBomTable(table, options) {
                         html += bValid;
                     }
 
+                    html += bEdit;
+                    html += bSubs;
+                    html += bDelt;
+
                     html += `</div>`;
 
                     return html;
@@ -490,6 +683,7 @@ function loadBomTable(table, options) {
         treeEnable: !options.editable,
         rootParentId: parent_id,
         idField: 'pk',
+        uniqueId: 'pk',
         parentIdField: 'parentId',
         treeShowField: 'sub_part',
         showColumns: true,
@@ -566,19 +760,27 @@ function loadBomTable(table, options) {
     // In editing mode, attached editables to the appropriate table elements
     if (options.editable) {
 
+        // Callback for "delete" button
         table.on('click', '.bom-delete-button', function() {
 
             var pk = $(this).attr('pk');
 
+            var html = `
+            <div class='alert alert-block alert-danger'>
+            {% trans "Are you sure you want to delete this BOM item?" %}
+            </div>`;
+
             constructForm(`/api/bom/${pk}/`, {
                 method: 'DELETE',
                 title: '{% trans "Delete BOM Item" %}',
+                preFormContent: html,
                 onSuccess: function() {
                     reloadBomTable(table);
                 }
             }); 
         });
 
+        // Callback for "edit" button
         table.on('click', '.bom-edit-button', function() {
 
             var pk = $(this).attr('pk');
@@ -595,6 +797,7 @@ function loadBomTable(table, options) {
             });
         });
 
+        // Callback for "validate" button
         table.on('click', '.bom-validate-button', function() {
 
             var pk = $(this).attr('pk');
@@ -613,5 +816,22 @@ function loadBomTable(table, options) {
                 }
             );
         });
+
+        // Callback for "substitutes" button
+        table.on('click', '.bom-substitutes-button', function() {
+            var pk = $(this).attr('pk');
+
+            var row = table.bootstrapTable('getRowByUniqueId', pk);
+            var subs = row.substitutes || [];
+
+            bomSubstitutesDialog(
+                pk,
+                subs,
+                {
+                    table: table,
+                    sub_part: row.sub_part,
+                }
+            );
+        });
     }
 }
diff --git a/InvenTree/templates/js/translated/build.js b/InvenTree/templates/js/translated/build.js
index d3be81e4e3..d3499deedf 100644
--- a/InvenTree/templates/js/translated/build.js
+++ b/InvenTree/templates/js/translated/build.js
@@ -208,15 +208,10 @@ function makeBuildOutputActionButtons(output, buildInfo, lines) {
 
         var pk = $(this).attr('pk');
 
-        launchModalForm(
-            `/build/${buildId}/unallocate/`,
-            {
-                success: reloadTable,
-                data: {
-                    output: pk,
-                }
-            }
-        );
+        unallocateStock(buildId, {
+            output: pk,
+            table: table,
+        });
     });
 
     $(panel).find(`#button-output-delete-${outputId}`).click(function() {
@@ -236,6 +231,49 @@ function makeBuildOutputActionButtons(output, buildInfo, lines) {
 }
 
 
+/*
+ * Unallocate stock against a particular build order
+ * 
+ * Options:
+ * - output: pk value for a stock item "build output"
+ * - bom_item: pk value for a particular BOMItem (build item)
+ */
+function unallocateStock(build_id, options={}) {
+
+    var url = `/api/build/${build_id}/unallocate/`;
+
+    var html = `
+    <div class='alert alert-block alert-warning'>
+    {% trans "Are you sure you wish to unallocate stock items from this build?" %}
+    </dvi>
+    `;
+
+    constructForm(url, {
+        method: 'POST',
+        confirm: true,
+        preFormContent: html,
+        fields: {
+            output: {
+                hidden: true,
+                value: options.output,
+            },
+            bom_item: {
+                hidden: true,
+                value: options.bom_item,
+            },
+        },
+        title: '{% trans "Unallocate Stock Items" %}',
+        onSuccess: function(response, opts) {
+            if (options.table) {
+                // Reload the parent table
+                $(options.table).bootstrapTable('refresh');
+            }
+        }
+    });
+
+}
+
+
 function loadBuildOrderAllocationTable(table, options={}) {
     /**
      * Load a table showing all the BuildOrder allocations for a given part
@@ -348,6 +386,17 @@ function loadBuildOutputAllocationTable(buildInfo, output, options={}) {
         table = `#allocation-table-${outputId}`;
     }
 
+    // Filters
+    var filters = loadTableFilters('builditems');
+
+    var params = options.params || {};
+
+    for (var key in params) {
+        filters[key] = params[key];
+    }
+
+    setupFilterList('builditems', $(table), options.filterTarget || null);
+
     // If an "output" is specified, then only "trackable" parts are allocated
     // Otherwise, only "untrackable" parts are allowed
     var trackable = ! !output;
@@ -458,17 +507,16 @@ function loadBuildOutputAllocationTable(buildInfo, output, options={}) {
 
         // Callback for 'unallocate' button
         $(table).find('.button-unallocate').click(function() {
-            var pk = $(this).attr('pk');
 
-            launchModalForm(`/build/${buildId}/unallocate/`,
-                {
-                    success: reloadTable,
-                    data: {
-                        output: outputId,
-                        part: pk,
-                    }
-                }
-            );
+            // Extract row data from the table
+            var idx = $(this).closest('tr').attr('data-index');
+            var row = $(table).bootstrapTable('getData')[idx];
+
+            unallocateStock(buildId, {
+                bom_item: row.pk,
+                output: outputId == 'untracked' ? null : outputId,
+                table: table,
+            });
         });
     }
 
@@ -726,6 +774,14 @@ function loadBuildOutputAllocationTable(buildInfo, output, options={}) {
 
                     html += makePartIcons(row.sub_part_detail);
 
+                    if (row.substitutes && row.substitutes.length > 0) {
+                        html += makeIconBadge('fa-exchange-alt', '{% trans "Substitute parts available" %}');
+                    }
+
+                    if (row.allow_variants) {
+                        html += makeIconBadge('fa-sitemap', '{% trans "Variant stock allowed" %}');
+                    }
+
                     return html;
                 }
             },
@@ -1021,12 +1077,12 @@ function allocateStockToBuild(build_id, part_id, bom_items, options={}) {
                         filters: {
                             bom_item: bom_item.pk,
                             in_stock: true,
-                            part_detail: false,
+                            part_detail: true,
                             location_detail: true,
                         },
                         model: 'stockitem',
                         required: true,
-                        render_part_detail: false,
+                        render_part_detail: true,
                         render_location_detail: true,
                         auto_fill: true,
                         adjustFilters: function(filters) {
diff --git a/InvenTree/templates/js/translated/filters.js b/InvenTree/templates/js/translated/filters.js
index 3e41003696..53429effea 100644
--- a/InvenTree/templates/js/translated/filters.js
+++ b/InvenTree/templates/js/translated/filters.js
@@ -283,10 +283,16 @@ function setupFilterList(tableKey, table, target) {
 
     element.append(`<button id='reload-${tableKey}' title='{% trans "Reload data" %}' class='btn btn-default filter-tag'><span class='fas fa-redo-alt'></span></button>`);
 
+    // If there are no filters defined for this table, exit now
+    if (jQuery.isEmptyObject(getAvailableTableFilters(tableKey))) {
+        return;
+    }
+
+    // If there are filters currently "in use", add them in!
     element.append(`<button id='${add}' title='{% trans "Add new filter" %}' class='btn btn-default filter-tag'><span class='fas fa-filter'></span></button>`);
 
     if (Object.keys(filters).length > 0) {
-        element.append(`<button id='${clear}' title='{% trans "Clear all filters" %}' class='btn btn-default filter-tag'><span class='fas fa-trash-alt'></span></button>`);
+        element.append(`<button id='${clear}' title='{% trans "Clear all filters" %}' class='btn btn-default filter-tag'><span class='fas fa-backspace icon-red'></span></button>`);
     }
 
     for (var key in filters) {
diff --git a/InvenTree/templates/js/translated/forms.js b/InvenTree/templates/js/translated/forms.js
index fecf5f1bd6..2483263219 100644
--- a/InvenTree/templates/js/translated/forms.js
+++ b/InvenTree/templates/js/translated/forms.js
@@ -1349,7 +1349,7 @@ function initializeRelatedField(field, fields, options) {
                 
                 // Allow custom run-time filter augmentation
                 if ('adjustFilters' in field) {
-                    query = field.adjustFilters(query);
+                    query = field.adjustFilters(query, options);
                 }
 
                 return query;
diff --git a/InvenTree/templates/js/translated/model_renderers.js b/InvenTree/templates/js/translated/model_renderers.js
index 33eef49e48..0bb0818a70 100644
--- a/InvenTree/templates/js/translated/model_renderers.js
+++ b/InvenTree/templates/js/translated/model_renderers.js
@@ -52,8 +52,6 @@ function renderStockItem(name, data, parameters, options) {
     if (data.part_detail) {
         image = data.part_detail.thumbnail || data.part_detail.image || blankImage();
     }
-
-    var html = '';
     
     var render_part_detail = true;
 
@@ -61,23 +59,10 @@ function renderStockItem(name, data, parameters, options) {
         render_part_detail = parameters['render_part_detail'];
     }
 
+    var part_detail = '';
+
     if (render_part_detail) {
-        html += `<img src='${image}' class='select2-thumbnail'>`;
-        html += ` <span>${data.part_detail.full_name || data.part_detail.name}</span>`;
-    }
-
-    html += '<span>';
-
-    if (data.serial && data.quantity == 1) {
-        html += `{% trans "Serial Number" %}: ${data.serial}`;
-    } else {
-        html += `{% trans "Quantity" %}: ${data.quantity}`;
-    }
-
-    html += '</span>';
-
-    if (render_part_detail && data.part_detail.description) {
-        html += `<p><small>${data.part_detail.description}</small></p>`;
+        part_detail = `<img src='${image}' class='select2-thumbnail'><span>${data.part_detail.full_name}</span> - `;
     }
 
     var render_stock_id = true;
@@ -86,8 +71,10 @@ function renderStockItem(name, data, parameters, options) {
         render_stock_id = parameters['render_stock_id'];
     }
 
+    var stock_id = '';
+    
     if (render_stock_id) {
-        html += `<span class='float-right'><small>{% trans "Stock ID" %}: ${data.pk}</small></span>`;
+        stock_id = `<span class='float-right'><small>{% trans "Stock ID" %}: ${data.pk}</small></span>`;
     }
 
     var render_location_detail = false;
@@ -96,10 +83,28 @@ function renderStockItem(name, data, parameters, options) {
         render_location_detail = parameters['render_location_detail'];
     }
 
+    var location_detail = '';
+
     if (render_location_detail && data.location_detail) {
-        html += `<span> - ${data.location_detail.name}</span>`;
+        location_detail = ` - (<em>${data.location_detail.name}</em>)`;
     }
 
+    var stock_detail = '';
+
+    if (data.serial && data.quantity == 1) {
+        stock_detail = `{% trans "Serial Number" %}: ${data.serial}`;
+    } else if (data.quantity == 0) {
+        stock_detail = `<span class='label-form label-red'>{% trans "No Stock"% }</span>`;
+    } else {
+        stock_detail = `{% trans "Quantity" %}: ${data.quantity}`;
+    }
+
+    var html = `
+    <span>
+        ${part_detail}${stock_detail}${location_detail}${stock_id}
+    </span>
+    `;
+
     return html;
 }
 
@@ -159,21 +164,25 @@ function renderPart(name, data, parameters, options) {
         html += ` - <i>${data.description}</i>`;
     }
 
-    var stock = '';
+    var extra = '';
 
     // Display available part quantity
     if (user_settings.PART_SHOW_QUANTITY_IN_FORMS) {
         if (data.in_stock == 0) {
-            stock = `<span class='label-form label-red'>{% trans "No Stock" %}</span>`;
+            extra += `<span class='label-form label-red'>{% trans "No Stock" %}</span>`;
         } else {
-            stock = `<span class='label-form label-green'>{% trans "In Stock" %}: ${data.in_stock}</span>`;
+            extra += `<span class='label-form label-green'>{% trans "Stock" %}: ${data.in_stock}</span>`;
         }
     }
 
+    if (!data.active) {
+        extra += `<span class='label-form label-red'>{% trans "Inactive" %}</span>`;
+    }
+
     html += `
     <span class='float-right'>
         <small>
-            ${stock}
+            ${extra}
             {% trans "Part ID" %}: ${data.pk}
             </small>
     </span>`;
diff --git a/InvenTree/templates/js/translated/part.js b/InvenTree/templates/js/translated/part.js
index aba3c46330..d7747a244f 100644
--- a/InvenTree/templates/js/translated/part.js
+++ b/InvenTree/templates/js/translated/part.js
@@ -592,7 +592,7 @@ function loadPartParameterTable(table, url, options) {
         filters[key] = params[key];
     }
 
-    // setupFilterLsit("#part-parameters", $(table));
+    // setupFilterList("#part-parameters", $(table));
 
     $(table).inventreeTable({
         url: url,
@@ -876,23 +876,7 @@ function loadPartTable(table, url, options={}) {
         switchable: false,
         formatter: function(value, row) {
 
-            var name = '';
-
-            if (row.IPN) {
-                name += row.IPN;
-                name += ' | ';
-            }
-
-            name += value;
-
-            if (row.revision) {
-                name += ' | ';
-                name += row.revision;
-            }
-
-            if (row.is_template) {
-                name = '<i>' + name + '</i>';
-            }
+            var name = row.full_name;
 
             var display = imageHoverIcon(row.thumbnail) + renderLink(name, '/part/' + row.pk + '/');
 
diff --git a/InvenTree/templates/navbar.html b/InvenTree/templates/navbar.html
index 3fae5cf0a0..a17ae0d804 100644
--- a/InvenTree/templates/navbar.html
+++ b/InvenTree/templates/navbar.html
@@ -3,12 +3,6 @@
 {% load i18n %}
 
 {% settings_value 'BARCODE_ENABLE' as barcodes %}
-{% settings_value 'BUILD_FUNCTION_ENABLE' as enable_build %}
-{% settings_value 'BUY_FUNCTION_ENABLE' as enable_buy %}
-{% settings_value 'SELL_FUNCTION_ENABLE' as enable_sell %}
-{% settings_value 'STOCK_FUNCTION_ENABLE' as enable_stock %}
-{% settings_value 'SO_FUNCTION_ENABLE' as enable_so %}
-{% settings_value 'PO_FUNCTION_ENABLE' as enable_po %}
 
 <nav class="navbar navbar-xs navbar-default navbar-fixed-top ">
   <div class="container-fluid">
@@ -28,32 +22,28 @@
         {% if roles.part.view %}
         <li><a href="{% url 'part-index' %}"><span class='fas fa-shapes icon-header'></span>{% trans "Parts" %}</a></li>
         {% endif %}
-        {% if roles.stock.view and enable_stock %}
+        {% if roles.stock.view %}
         <li><a href="{% url 'stock-index' %}"><span class='fas fa-boxes icon-header'></span>{% trans "Stock" %}</a></li>
         {% endif %}
-        {% if roles.build.view and enable_build %}
+        {% if roles.build.view %}
         <li><a href="{% url 'build-index' %}"><span class='fas fa-tools icon-header'></span>{% trans "Build" %}</a></li>
         {% endif %}
-        {% if roles.purchase_order.view and enable_buy %}
+        {% if roles.purchase_order.view %}
         <li class='nav navbar-nav'>
           <a class='dropdown-toggle' data-toggle='dropdown' href='#'><span class='fas fa-shopping-cart icon-header'></span>{% trans "Buy" %}</a>
           <ul class='dropdown-menu'>
             <li><a href="{% url 'supplier-index' %}"><span class='fas fa-building icon-header'></span>{% trans "Suppliers" %}</a></li>
             <li><a href="{% url 'manufacturer-index' %}"><span class='fas fa-industry icon-header'></span>{% trans "Manufacturers" %}</a></li>
-            {% if enable_po %}
             <li><a href="{% url 'po-index' %}"><span class='fas fa-list icon-header'></span>{% trans "Purchase Orders" %}</a></li>
-            {% endif %}
           </ul>
         </li>
         {% endif %}
-        {% if roles.sales_order.view and enable_sell %}
+        {% if roles.sales_order.view %}
         <li class='nav navbar-nav'>
           <a class='dropdown-toggle' data-toggle='dropdown' href='#'><span class='fas fa-truck icon-header'></span>{% trans "Sell" %}</a>
           <ul class='dropdown-menu'>
             <li><a href="{% url 'customer-index' %}"><span class='fas fa-user-tie icon-header'></span>{% trans "Customers" %}</a>
-            {% if enable_so %}
             <li><a href="{% url 'so-index' %}"><span class='fas fa-list icon-header'></span>{% trans "Sales Orders" %}</a></li>
-            {% endif %}
           </ul>
         </li>
         {% endif %}
diff --git a/InvenTree/users/models.py b/InvenTree/users/models.py
index 73a7561153..d31f2a9905 100644
--- a/InvenTree/users/models.py
+++ b/InvenTree/users/models.py
@@ -81,6 +81,7 @@ class RuleSet(models.Model):
         'part': [
             'part_part',
             'part_bomitem',
+            'part_bomitemsubstitute',
             'part_partattachment',
             'part_partsellpricebreak',
             'part_partinternalpricebreak',
@@ -110,6 +111,7 @@ class RuleSet(models.Model):
             'part_part',
             'part_partcategory',
             'part_bomitem',
+            'part_bomitemsubstitute',
             'build_build',
             'build_builditem',
             'build_buildorderattachment',
diff --git a/README.md b/README.md
index a8d429c249..0dccc03183 100644
--- a/README.md
+++ b/README.md
@@ -20,6 +20,7 @@ However, powerful business logic works in the background to ensure that stock tr
 # Docker
 
 [![Docker Pulls](https://img.shields.io/docker/pulls/inventree/inventree)](https://hub.docker.com/r/inventree/inventree)
+![Docker Build](https://github.com/inventree/inventree/actions/workflows/docker_latest.yaml/badge.svg)
 
 InvenTree is [available via Docker](https://hub.docker.com/r/inventree/inventree). Read the [docker guide](https://inventree.readthedocs.io/en/latest/start/docker/) for full details.
 
diff --git a/requirements.txt b/requirements.txt
index 24786cbd7a..9fa4149aba 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -35,6 +35,7 @@ python-barcode[images]==0.13.1  # Barcode generator
 qrcode[pil]==6.1                # QR code generator
 django-q==1.3.4                 # Background task scheduling
 django-formtools==2.3           # Form wizard tools
+cryptography==3.4.8             # Cryptography support
 django-allauth==0.45.0          # SSO for external providers via OpenID
 
 inventree                       # Install the latest version of the InvenTree API python library