diff --git a/progmgr/grpupdat.h b/progmgr/grpupdat.h
new file mode 100644
index 0000000..9c6d8d0
--- /dev/null
+++ b/progmgr/grpupdat.h
@@ -0,0 +1,38 @@
+/* * * * * * * *\
+	GRPUPDAT.H -
+		Copyright (c) 2023 freedom7341, Vortesys
+	DESCRIPTION -
+		Header containing classic program group structures
+		in order to facilitate conversion to the new format.
+	LICENSE INFORMATION -
+		MIT License, see LICENSE.txt in the root folder
+\* * * * * * * */
+
+/* Pragmas */
+#pragma once
+
+/* Includes */
+#include <wtypes.h>
+
+/* Definitions */
+// Group signatures
+#define OLDGRP_SIGNATURE 0x43554D50L // PMUC
+
+/* Structures */
+// Old group format, .GRP
+typedef struct _OLDGROUP {
+	DWORD dwMagic; // Set to OLDGRP_SIGNATURE
+	WORD wCheckSum; // Seemingly unused
+    WORD cbGroup; // Size of group
+    RECT rcNormal; // Window rect
+    POINT ptMin; // Minimized window position
+    WORD nCmdShow; // Min/max state
+    WORD pName; // Group name
+    WORD cxIcon; // Icon width
+    WORD cyIcon; // Icon height
+    WORD wIconFormat;
+    WORD wReserved; // Unused
+
+    WORD cItems; // Number of items
+    WORD rgiItems[1]; // Array of item offsets
+} OLDGROUP, * POLDGROUP;
diff --git a/progmgr/progmgr.vcxproj b/progmgr/progmgr.vcxproj
index d7c89ea..64aae2a 100644
--- a/progmgr/progmgr.vcxproj
+++ b/progmgr/progmgr.vcxproj
@@ -160,6 +160,7 @@
   </ItemDefinitionGroup>
   <ItemGroup>
     <ClInclude Include="group.h" />
+    <ClInclude Include="grpupdat.h" />
     <ClInclude Include="progmgr.h" />
     <ClInclude Include="registry.h" />
     <ClInclude Include="resource.h" />
diff --git a/progmgr/progmgr.vcxproj.filters b/progmgr/progmgr.vcxproj.filters
index 6af6897..ff994fe 100644
--- a/progmgr/progmgr.vcxproj.filters
+++ b/progmgr/progmgr.vcxproj.filters
@@ -30,6 +30,9 @@
     <ClInclude Include="group.h">
       <Filter>Header Files</Filter>
     </ClInclude>
+    <ClInclude Include="grpupdat.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <ClCompile Include="progmgr.c">