Patch 1.12.1 is the final stable version of original WoW. It includes:
This client is the base for nearly every major private server, such as Elysium Project and Everlook . Features of a Portable "Repack" WoW Vanilla Client 1.12.1 Portable Free Download -REPACK
A "Portable Repack" differs from standard installers by being self-contained. [Client] Why 1.12.1? - OwnedCore Patch 1