every time I host or try to join a multiplayer game, an error messages pops up saying check mod sum, you may be running of a different version than the host, tried hosting with a friend who also has 0.88.8 and same issue, even when I uploaded the file to mega and had him download it, and vice versa.

hey i had a similar issue, and even uninstalling the game and deleting the files won't work, you'd have to do a reset of your computer through windows recovery and reinstall even back on to the computer, I don't know about you, but i find it to be worth it, so i did, and that was the only thing i found that worked