diff --git a/Wabbajack.Common/Consts.cs b/Wabbajack.Common/Consts.cs
index 13827c09..c4b227ec 100644
--- a/Wabbajack.Common/Consts.cs
+++ b/Wabbajack.Common/Consts.cs
@@ -144,6 +144,8 @@ namespace Wabbajack.Common
         public static Uri WabbajackOrg = new Uri("https://www.wabbajack.org/");
         
         public static long UPLOADED_FILE_BLOCK_SIZE = (long)1024 * 1024 * 2;
+        
+        public static string ArchiveUpdatesCDNFolder = "archive_updates";
 
     }
 }
diff --git a/Wabbajack.Common/Paths.cs b/Wabbajack.Common/Paths.cs
index 612e0ed1..eae25994 100644
--- a/Wabbajack.Common/Paths.cs
+++ b/Wabbajack.Common/Paths.cs
@@ -340,7 +340,7 @@ namespace Wabbajack.Common
         public async Task WriteAllAsync(Stream data, bool disposeAfter = true)
         {
             await using var fs = Create();
-            await fs.CopyToAsync(data);
+            await data.CopyToAsync(fs);
             if (disposeAfter) await data.DisposeAsync();
         }
 
diff --git a/Wabbajack.Lib/Downloaders/HTTPDownloader.cs b/Wabbajack.Lib/Downloaders/HTTPDownloader.cs
index 912306a2..1a104d5b 100644
--- a/Wabbajack.Lib/Downloaders/HTTPDownloader.cs
+++ b/Wabbajack.Lib/Downloaders/HTTPDownloader.cs
@@ -5,6 +5,7 @@ using System.Linq;
 using System.Net.Http;
 using System.Net.Http.Headers;
 using System.Threading.Tasks;
+using AngleSharp.Css;
 using Newtonsoft.Json;
 using Wabbajack.Common;
 using Wabbajack.Common.Serialization.Json;
@@ -46,7 +47,7 @@ namespace Wabbajack.Lib.Downloaders
         }
 
         [JsonName("HttpDownloader")]
-        public class State : AbstractDownloadState
+        public class State : AbstractDownloadState, IUpgradingState
         {
             public string Url { get; }
 
@@ -210,6 +211,28 @@ TOP:
                     return new [] {"[General]", $"directURL={Url}"};
 
             }
+
+            public async Task<(Archive? Archive, TempFile NewFile)> FindUpgrade(Archive a)
+            {
+                var tmpFile = new TempFile();
+                
+                var newArchive = new Archive(this) {Name = a.Name};
+                
+                if (!await Download(newArchive, tmpFile.Path))
+                    return default;
+
+                newArchive.Hash = await tmpFile.Path.FileHashAsync();
+                newArchive.Size = tmpFile.Path.Size;
+
+                return (newArchive, tmpFile);
+
+            }
+
+            public bool ValidateUpgrade(AbstractDownloadState newArchiveState)
+            {
+                var httpState = (State)newArchiveState;
+                return httpState.Url == Url;
+            }
         }
     }
 }
diff --git a/Wabbajack.Server.Test/ModlistUpdater.cs b/Wabbajack.Server.Test/ModlistUpdater.cs
index 418af94e..40463b75 100644
--- a/Wabbajack.Server.Test/ModlistUpdater.cs
+++ b/Wabbajack.Server.Test/ModlistUpdater.cs
@@ -73,8 +73,60 @@ namespace Wabbajack.Server.Test
             await Assert.ThrowsAsync<HttpException>(async () => await ClientAPI.GetModUpgrade(oldArchive, newArchive, TimeSpan.Zero, TimeSpan.Zero));
             Assert.Equal(1, await patcher.Execute());
 
-            Assert.Equal(new Uri("https://wabbajacktest.b-cdn.net/archive_upgrades/79223277e28e1b7b_3286c571d95f5666"),await ClientAPI.GetModUpgrade(oldArchive, newArchive, TimeSpan.Zero, TimeSpan.Zero));
+            Assert.Equal(new Uri("https://wabbajacktest.b-cdn.net/archive_updates/79223277e28e1b7b_3286c571d95f5666"),await ClientAPI.GetModUpgrade(oldArchive, newArchive, TimeSpan.Zero, TimeSpan.Zero));
+        }
 
+                [Fact]
+        public async Task TestEndToEndArchiveUpdating()
+        {
+            var modLists = await MakeModList();
+            Consts.ModlistMetadataURL = modLists.ToString();
+            
+            
+            var downloader = Fixture.GetService<ArchiveDownloader>();
+            var archiver = Fixture.GetService<ArchiveMaintainer>();
+            var patcher = Fixture.GetService<PatchBuilder>();
+            
+            var sql = Fixture.GetService<SqlService>();
+            var oldFileData = Encoding.UTF8.GetBytes("Cheese for Everyone!");
+            var newFileData = Encoding.UTF8.GetBytes("Forks for Everyone!");
+            var oldDataHash = oldFileData.xxHash();
+            var newDataHash = newFileData.xxHash();
+            
+            await "upgrading_file.txt".RelativeTo(Fixture.ServerPublicFolder).WriteAllBytesAsync(oldFileData);
+            
+            var oldArchive = new Archive(new HTTPDownloader.State(MakeURL("upgrading_file.txt")))
+            {
+                Size = oldFileData.Length,
+                Hash = oldDataHash
+            };
+
+            await IngestData(archiver, oldFileData);
+            await sql.EnqueueDownload(oldArchive);
+            var oldDownload = await sql.GetNextPendingDownload();
+            await oldDownload.Finish(sql);
+            
+            
+            // Now update the file
+            await "upgrading_file.txt".RelativeTo(Fixture.ServerPublicFolder).WriteAllBytesAsync(newFileData);
+
+
+            using var tempFile = new TempFile();
+            var pendingRequest = DownloadDispatcher.DownloadWithPossibleUpgrade(oldArchive, tempFile.Path);
+
+            for (var times = 0; await downloader.Execute() == 0 && times < 40; times ++)
+            {
+                await Task.Delay(TimeSpan.FromMilliseconds(200));
+            }
+
+            
+            for (var times = 0; await patcher.Execute() == 0 && times < 40; times ++)
+            {
+                await Task.Delay(TimeSpan.FromMilliseconds(200));
+            }
+
+            Assert.True(await pendingRequest);
+            Assert.Equal(oldDataHash, await tempFile.Path.FileHashAsync());
         }
 
         private async Task IngestData(ArchiveMaintainer am, byte[] data)
diff --git a/Wabbajack.Server/Controllers/ModUpgrade.cs b/Wabbajack.Server/Controllers/ModUpgrade.cs
index ea6c919e..d7de7265 100644
--- a/Wabbajack.Server/Controllers/ModUpgrade.cs
+++ b/Wabbajack.Server/Controllers/ModUpgrade.cs
@@ -44,7 +44,7 @@ namespace Wabbajack.BuildServer.Controllers
                 {
                     return
                         Ok(
-                            $"https://{_settings.BunnyCDN_StorageZone}.b-cdn.net/archive_upgrades/{request.OldArchive.Hash.ToHex()}_{request.NewArchive.Hash.ToHex()}");
+                            $"https://{_settings.BunnyCDN_StorageZone}.b-cdn.net/{Consts.ArchiveUpdatesCDNFolder}/{request.OldArchive.Hash.ToHex()}_{request.NewArchive.Hash.ToHex()}");
                 }
 
                 return NotFound("Patch creation failed");
diff --git a/Wabbajack.Server/Services/PatchBuilder.cs b/Wabbajack.Server/Services/PatchBuilder.cs
index b150d73c..aa9961e8 100644
--- a/Wabbajack.Server/Services/PatchBuilder.cs
+++ b/Wabbajack.Server/Services/PatchBuilder.cs
@@ -50,7 +50,7 @@ namespace Wabbajack.Server.Services
                     _maintainer.TryGetPath(patch.Src.Archive.Hash, out var srcPath);
                     _maintainer.TryGetPath(patch.Dest.Archive.Hash, out var destPath);
 
-                    var patchName = $"archive_updates\\{patch.Src.Archive.Hash}_{patch.Dest.Archive.Hash}";
+                    var patchName = $"{Consts.ArchiveUpdatesCDNFolder}\\{patch.Src.Archive.Hash.ToHex()}_{patch.Dest.Archive.Hash.ToHex()}";
 
                     using var sigFile = new TempFile();
                     await using var srcStream = srcPath.OpenShared();
@@ -58,8 +58,8 @@ namespace Wabbajack.Server.Services
                     await using var sigStream = sigFile.Path.Create();
                     using var ftpClient = await GetBunnyCdnFtpClient();
 
-                    if (!await ftpClient.DirectoryExistsAsync("archive_updates")) 
-                        await ftpClient.CreateDirectoryAsync("archive_updates");
+                    if (!await ftpClient.DirectoryExistsAsync(Consts.ArchiveUpdatesCDNFolder)) 
+                        await ftpClient.CreateDirectoryAsync(Consts.ArchiveUpdatesCDNFolder);
 
                     
                     await using var patchOutput = await ftpClient.OpenWriteAsync(patchName);