diff --git a/UnrealReZen/Core/FIoPack.cs b/UnrealReZen/Core/FIoPack.cs
index 4e7c68a..a318d75 100644
--- a/UnrealReZen/Core/FIoPack.cs
+++ b/UnrealReZen/Core/FIoPack.cs
@@ -1,5 +1,7 @@
 using CUE4Parse.Encryption.Aes;
 using CUE4Parse.UE4.IO.Objects;
+using CUE4Parse.UE4.Objects.Core.Misc;
+using CUE4Parse.UE4.Versions;
 using System.Globalization;
 using System.IO.MemoryMappedFiles;
 using System.Text;
@@ -10,8 +12,10 @@ namespace UnrealReZen.Core
 {
     public static class Packer
     {
-        public static int PackToCasToc(string dir, Dependency m, string outFilename, string compression, FAesKey aes, string mountPoint, FIoDependencyFormat depver)
+        public static int PackToCasToc(string dir, Dependency m, string outFilename, string compression, FAesKey aes, string mountPoint, EGame gameVer)
         {
+            FIoDependencyFormat depver = gameVer >= EGame.GAME_UE5_0 ? FIoDependencyFormat.UE5 : FIoDependencyFormat.UE4;
+
             var fdata = new List<AssetMetadata>();
             AssetMetadata newEntry;
             Constants.MountPoint = mountPoint;
@@ -50,7 +54,7 @@ public static int PackToCasToc(string dir, Dependency m, string outFilename, str
                 File.WriteAllBytes(Path.ChangeExtension(outFilename, ".ucas"), encrypted);
             }
 
-            var utocBytes = fdata.ConstructUtocFile(compression, aes);
+            var utocBytes = fdata.ConstructUtocFile(compression, aes, gameVer);
             File.WriteAllBytes(outFilename, utocBytes);
             File.WriteAllBytes(Path.ChangeExtension(outFilename, ".pak"), PakHolder.Packed_P);
             return fdata.Count;
@@ -217,7 +221,7 @@ public static byte[] DeparseDirectoryIndex(List<AssetMetadata> files)
             return wrapper.ToBytes();
         }
 
-        public static byte[] ConstructUtocFile(this List<AssetMetadata> files, string compression, FAesKey AESKey)
+        public static byte[] ConstructUtocFile(this List<AssetMetadata> files, string compression, FAesKey AESKey, EGame gameVer)
         {
             var udata = new UToc(new UTocHeader(), [], "", []);
 
@@ -241,7 +245,8 @@ public static byte[] ConstructUtocFile(this List<AssetMetadata> files, string co
             for (var i = 0; i < files.Count; i++)
             {
                 compressedBlocksCount += files[i].CompressionBlocks.Count;
-                if (files[i].ChunkID.Type == 10)
+                if ((gameVer < EGame.GAME_UE5_0 && files[i].ChunkID.Type == (byte)EIoChunkType.ContainerHeader) ||
+                    gameVer >= EGame.GAME_UE5_0 && files[i].ChunkID.Type == (byte)EIoChunkType5.ContainerHeader)
                 {
                     containerIndex = i;
                 }
diff --git a/UnrealReZen/Program.cs b/UnrealReZen/Program.cs
index 1ae64e6..331eb18 100644
--- a/UnrealReZen/Program.cs
+++ b/UnrealReZen/Program.cs
@@ -139,7 +139,9 @@ static void RunOptionsAndReturnExitCode(Options opts)
             Dependency m = new() { Deps = new DependenciesData { ChunkIDToDependencies = [] }, Files = [] };
             List<string> FilesToRepack = new(Directory.GetFiles(opts.ContentPath, "*", SearchOption.AllDirectories));
             var newContainerID = opts.ContainerId ?? CryptographyHelpers.RandomUlong();
-            m.Files.Add(new ManifestFile { ChunkID = new FIoChunkID(newContainerID, 0, 0, (byte)EIoChunkType.ContainerHeader), Filepath = Constants.DepFileName });
+
+            byte type = (EGame)engineVersion >= EGame.GAME_UE5_0 ? (byte)EIoChunkType5.ContainerHeader : (byte)EIoChunkType.ContainerHeader;
+            m.Files.Add(new ManifestFile { ChunkID = new FIoChunkID(newContainerID, 0, 0, type), Filepath = Constants.DepFileName });
             m.Deps.ThisPackageID = newContainerID;
             if (FilesToRepack.Count == 0)
             {
@@ -173,7 +175,7 @@ static void RunOptionsAndReturnExitCode(Options opts)
                 }
             }
             Log.Information("Packing files...");
-            Packer.PackToCasToc(opts.ContentPath, m, opts.OutputPath, opts.CompressionFormat, aesKey, opts.MountPoint, (EGame)engineVersion > EGame.GAME_UE4_LATEST ? FIoDependencyFormat.UE5 : FIoDependencyFormat.UE4);
+            Packer.PackToCasToc(opts.ContentPath, m, opts.OutputPath, opts.CompressionFormat, aesKey, opts.MountPoint, (EGame)engineVersion);
             Console.WriteLine($"Done! {FilesToRepack.Count} file(s) packed");
 
         }