@Salaxaddin,
In MMH55 development to this point a number of changes were made to make creature upgrades to differ from each other. I can admit that certain creature upgrades difference may be more niche than others, or there are creatures which upgrades are used for the same tactics even though stat wise they are different.
Without giving a proper examples which upgrades can be changed and how to be made better I cannot elaborate further.
But to answer your question simply - MMH55 update branch will stay separate.