What is the difference between the houdini engine for 3ds max being released with Houdini 17 and the github plugin that has been around for some time?

GitHub(Hideki Suzuki), so you can get it at the link below
https://github.com/Ali2k/HoudiniEngineFor3dsMax [github.com]

the new one is from SideFX directly and not from a third party developer one man show…

Was the github plugin technically “Houdini Engine” working inside of 3ds max?

yes it was