diff --git a/.editorconfig b/.editorconfig
index 9270fbad..5b46bd60 100644
--- a/.editorconfig
+++ b/.editorconfig
@@ -121,4 +121,67 @@ csharp_preserve_single_line_blocks = true
 # CS4014: Task not awaited
 dotnet_diagnostic.CS4014.severity = error
 # CS1998: Async function does not contain await
-dotnet_diagnostic.CS1998.severity = silent
\ No newline at end of file
+dotnet_diagnostic.CS1998.severity = silent
+
+###############################
+# C# Nullability              #
+###############################
+# CS8602: Dereference of a possibly null reference.
+dotnet_diagnostic.CS8602.severity = error
+
+# CS8600: Converting null literal or possible null value to non-nullable type.
+dotnet_diagnostic.CS8600.severity = error
+
+# CS8619: Nullability of reference types in value doesn't match target type.
+dotnet_diagnostic.CS8619.severity = error
+
+# CS8603: Possible null reference return.
+dotnet_diagnostic.CS8603.severity = error
+
+# CS8625: Cannot convert null literal to non-nullable reference type.
+dotnet_diagnostic.CS8625.severity = error
+
+# CS8653: A default expression introduces a null value for a type parameter.
+dotnet_diagnostic.CS8653.severity = silent
+
+# CS8601: Possible null reference assignment.
+dotnet_diagnostic.CS8601.severity = error
+
+# CS8604: Possible null reference argument.
+dotnet_diagnostic.CS8604.severity = error
+
+# CS8622: Nullability of reference types in type of parameter doesn't match the target delegate.
+dotnet_diagnostic.CS8622.severity = error
+
+# CS8610: Nullability of reference types in type of parameter doesn't match overridden member.
+dotnet_diagnostic.CS8610.severity = error
+
+# CS8618: Non-nullable field is uninitialized. Consider declaring as nullable.
+dotnet_diagnostic.CS8618.severity = error
+
+# CS8629: Nullable value type may be null.
+dotnet_diagnostic.CS8629.severity = error
+
+# CS8620: Argument cannot be used for parameter due to differences in the nullability of reference types.
+dotnet_diagnostic.CS8620.severity = error
+
+# CS8614: Nullability of reference types in type of parameter doesn't match implicitly implemented member.
+dotnet_diagnostic.CS8614.severity = error
+
+# CS8617: Nullability of reference types in type of parameter doesn't match implemented member.
+dotnet_diagnostic.CS8617.severity = error
+
+# CS8611: Nullability of reference types in type of parameter doesn't match partial method declaration.
+dotnet_diagnostic.CS8611.severity = error
+
+# CS8597: Thrown value may be null.
+dotnet_diagnostic.CS8597.severity = error
+
+# CS8609: Nullability of reference types in return type doesn't match overridden member.
+dotnet_diagnostic.CS8609.severity = error
+
+# CS8714: The type cannot be used as type parameter in the generic type or method. Nullability of type argument doesn't match 'notnull' constraint.
+dotnet_diagnostic.CS8714.severity = error
+
+# CS8605: Unboxing a possibly null value.
+dotnet_diagnostic.CS8605.severity = error 
\ No newline at end of file
diff --git a/Wabbajack.CLI/CLIUtils.cs b/Wabbajack.CLI/CLIUtils.cs
index c9a081e8..8f20180e 100644
--- a/Wabbajack.CLI/CLIUtils.cs
+++ b/Wabbajack.CLI/CLIUtils.cs
@@ -1,9 +1,21 @@
 using System;
+using Wabbajack.CLI.Verbs;
 
 namespace Wabbajack.CLI
 {
+    [AttributeUsage(AttributeTargets.Property)]
+    internal class FileAttribute : Attribute { }
+
+    [AttributeUsage(AttributeTargets.Property)]
+    internal class DirectoryAttribute : Attribute { }
+
     internal static class CLIUtils
     {
+        internal static bool VerifyArguments(AVerb verb)
+        {
+            return true;
+        }
+
         internal static void Log(string msg, bool newLine = true)
         {
             //TODO: maybe also write to a log file?
diff --git a/Wabbajack.CLI/Verbs/AVerb.cs b/Wabbajack.CLI/Verbs/AVerb.cs
index 5d341f0a..5693a520 100644
--- a/Wabbajack.CLI/Verbs/AVerb.cs
+++ b/Wabbajack.CLI/Verbs/AVerb.cs
@@ -1,6 +1,4 @@
-using System.Text;
-using System.Threading;
-using System.Threading.Tasks;
+using System.Threading.Tasks;
 
 namespace Wabbajack.CLI.Verbs
 {
diff --git a/Wabbajack.CLI/Verbs/ChangeDownload.cs b/Wabbajack.CLI/Verbs/ChangeDownload.cs
index 966dfad9..f974d308 100644
--- a/Wabbajack.CLI/Verbs/ChangeDownload.cs
+++ b/Wabbajack.CLI/Verbs/ChangeDownload.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Diagnostics;
 using System.IO;
 using System.Linq;
 using System.Text;
@@ -18,16 +19,16 @@ namespace Wabbajack.CLI.Verbs
     public class ChangeDownload : AVerb
     {
         [Option("input", Required = true, HelpText = "Input folder containing the downloads you want to move")]
-        public string Input { get; set; }
+        public string? Input { get; set; }
 
         [Option("output", Required = true, HelpText = "Output folder the downloads should be transferred to")]
-        public string Output { get; set; }
+        public string? Output { get; set; }
 
         [Option("modlist", Required = true, HelpText = "The Modlist, can either be a .wabbajack or a modlist.txt file")]
-        public string Modlist { get; set; }
+        public string? Modlist { get; set; }
 
         [Option("mods", Required = false, HelpText = "Mods folder location if the provided modlist file is an MO2 modlist.txt")]
-        public string Mods { get; set; }
+        public string? Mods { get; set; }
 
         [Option("copy", Default = true, HelpText = "Whether to copy the files", SetName = "copy")]
         public bool Copy { get; set; }
@@ -69,13 +70,13 @@ namespace Wabbajack.CLI.Verbs
                 Directory.CreateDirectory(Output);
             }
 
-            if (!Modlist.EndsWith(Consts.ModListExtension) && !Modlist.EndsWith("modlist.txt"))
+            if (Modlist != null && (!Modlist.EndsWith(Consts.ModListExtension) && !Modlist.EndsWith("modlist.txt")))
                 return CLIUtils.Exit($"The file {Modlist} is not a valid modlist file!", -1);
 
             if (Copy && Move)
                 return CLIUtils.Exit("You can't set both copy and move flags!", -1);
 
-            var isModlist = Modlist.EndsWith(Consts.ModListExtension);
+            var isModlist = Modlist != null && Modlist.EndsWith(Consts.ModListExtension);
 
             var list = new List<TransferFile>();
 
diff --git a/Wabbajack.CLI/Verbs/Changelog.cs b/Wabbajack.CLI/Verbs/Changelog.cs
new file mode 100644
index 00000000..794e92ee
--- /dev/null
+++ b/Wabbajack.CLI/Verbs/Changelog.cs
@@ -0,0 +1,24 @@
+using System;
+using System.Threading.Tasks;
+using CommandLine;
+
+namespace Wabbajack.CLI.Verbs
+{
+    [Verb("changelog", HelpText = "Generate a changelog using two different versions of the same Modlist.")]
+    public class Changelog : AVerb
+    {
+        [Option("original", Required = true, HelpText = "The original/previous modlist")]
+        public string? Original { get; set; }
+
+        [Option("update", Required = true, HelpText = "The current/updated modlist")]
+        public string? Update { get; set; }
+
+        [Option('o', "output", Required = false, HelpText = "The output file")]
+        public string? Output { get; set; }
+
+        protected override Task<int> Run()
+        {
+            throw new NotImplementedException();
+        }
+    }
+}
diff --git a/Wabbajack.CLI/Verbs/Decrypt.cs b/Wabbajack.CLI/Verbs/Decrypt.cs
index d0d0126d..388207d0 100644
--- a/Wabbajack.CLI/Verbs/Decrypt.cs
+++ b/Wabbajack.CLI/Verbs/Decrypt.cs
@@ -9,11 +9,11 @@ namespace Wabbajack.CLI.Verbs
     public class Decrypt : AVerb
     {
         [Option('n', "name", Required = true, HelpText = @"Credential to encrypt and store in AppData\Local\Wabbajack")]
-        public string Name { get; set; }
+        public string? Name { get; set; }
 
         
         [Option('o', "output", Required = true, HelpText = @"Output file for the decrypted data")]
-        public string Output { get; set; }
+        public string? Output { get; set; }
 
         protected override async Task<int> Run()
         {
diff --git a/Wabbajack.CLI/Verbs/DeleteFile.cs b/Wabbajack.CLI/Verbs/DeleteFile.cs
index c89b698a..124e9f94 100644
--- a/Wabbajack.CLI/Verbs/DeleteFile.cs
+++ b/Wabbajack.CLI/Verbs/DeleteFile.cs
@@ -9,7 +9,8 @@ namespace Wabbajack.CLI.Verbs
     public class DeleteFile : AVerb
     {
         [Option('n', "name", Required = true, HelpText = @"Full name (as returned by my-files) of the file")]
-        public string Name { get; set; }
+        public string? Name { get; set; }
+
         protected override async Task<int> Run()
         {
             Console.WriteLine(await AuthorAPI.DeleteFile(Name));
diff --git a/Wabbajack.CLI/Verbs/DownloadUrl.cs b/Wabbajack.CLI/Verbs/DownloadUrl.cs
index 3a957fd2..f29ef59a 100644
--- a/Wabbajack.CLI/Verbs/DownloadUrl.cs
+++ b/Wabbajack.CLI/Verbs/DownloadUrl.cs
@@ -14,10 +14,10 @@ namespace Wabbajack.CLI.Verbs
     public class DownloadUrl : AVerb
     {
         [Option('u', "url", Required = true, HelpText = "Url to download")]
-        public Uri Url { get; set; }
+        public Uri? Url { get; set; }
 
         [Option('o', "output", Required = true, HelpText = "Output file name")]
-        public string Output { get; set; }
+        public string? Output { get; set; }
 
         protected override async Task<int> Run()
         {
diff --git a/Wabbajack.CLI/Verbs/Encrypt.cs b/Wabbajack.CLI/Verbs/Encrypt.cs
index ace41e2a..9213349f 100644
--- a/Wabbajack.CLI/Verbs/Encrypt.cs
+++ b/Wabbajack.CLI/Verbs/Encrypt.cs
@@ -9,10 +9,10 @@ namespace Wabbajack.CLI.Verbs
     public class Encrypt : AVerb
     {
         [Option('n', "name", Required = true, HelpText = @"Credential to encrypt and store in AppData\Local\Wabbajack")]
-        public string Name { get; set; }
+        public string? Name { get; set; }
         
         [Option('i', "input", Required = true, HelpText = @"Source data file name")]
-        public string Input { get; set; }
+        public string? Input { get; set; }
 
         protected override async Task<int> Run()
         {
diff --git a/Wabbajack.CLI/Verbs/Validate.cs b/Wabbajack.CLI/Verbs/Validate.cs
index 5a21e0af..141c9464 100644
--- a/Wabbajack.CLI/Verbs/Validate.cs
+++ b/Wabbajack.CLI/Verbs/Validate.cs
@@ -1,11 +1,9 @@
 using System;
-using System.Reactive.Linq;
 using System.Threading.Tasks;
 using CommandLine;
 using Wabbajack.Common;
 using Wabbajack.Lib;
 using Wabbajack.Lib.Validation;
-using Wabbajack.VirtualFileSystem;
 using File = Alphaleonis.Win32.Filesystem.File;
 
 namespace Wabbajack.CLI.Verbs
@@ -14,12 +12,11 @@ namespace Wabbajack.CLI.Verbs
     public class Validate : AVerb
     {
         [Option('i', "input", Required = true, HelpText = @"Modlist file")]
-        public string Input { get; set; }
+        public string? Input { get; set; }
 
         /// <summary>
         /// Runs the Validation of a Modlist
         /// </summary>
-        /// <param name="opts"></param>
         /// <returns>
         /// <para>
         /// <c>-1</c> bad Input
@@ -33,7 +30,7 @@ namespace Wabbajack.CLI.Verbs
                 return CLIUtils.Exit($"The file {Input} does not exist!", -1);
 
 
-            if (!Input.EndsWith(Consts.ModListExtension))
+            if (Input != null && !Input.EndsWith(Consts.ModListExtension))
                 return CLIUtils.Exit($"The file {Input} does not end with {Consts.ModListExtension}!", -1);
 
             ModList modlist;
diff --git a/Wabbajack.CLI/Wabbajack.CLI.csproj b/Wabbajack.CLI/Wabbajack.CLI.csproj
index 177a680f..ed51c614 100644
--- a/Wabbajack.CLI/Wabbajack.CLI.csproj
+++ b/Wabbajack.CLI/Wabbajack.CLI.csproj
@@ -12,6 +12,8 @@
         <Description>An automated ModList installer</Description>
         <PublishReadyToRun>true</PublishReadyToRun>        
         <RuntimeIdentifier>win10-x64</RuntimeIdentifier>
+        <LangVersion>8.0</LangVersion>
+        <Nullable>enable</Nullable>
     </PropertyGroup>
 
     <ItemGroup>