Forcing engine version

Force engine compatibility

An epic official unreal engine is incompatible with an engine built from source, but this is only because the version mismatch. In order to forcibly set the engine version modify Engine/Source/Runtime/Launch/Resource/Version.h

You just need to determine the official version number and manually enter it into the Version file. This is an example diff to force the version to match the official 4.12.3 version:

--- a/Engine/Source/Runtime/Launch/Resources/Version.h
+++ b/Engine/Source/Runtime/Launch/Resources/Version.h
@@ -8,7 +8,7 @@

 #define ENGINE_IS_LICENSEE_VERSION 0

-#define BUILT_FROM_CHANGELIST 0
+#define BUILT_FROM_CHANGELIST 3013449
 #define BRANCH_NAME "UE4"

 #define ENGINE_IS_PROMOTED_BUILD (BUILT_FROM_CHANGELIST > 0)