I am having some problems when removing blocks from my mod in 1.16.1 worlds. If I host a server with a world that used to have a block which is not removed, or if I remove a mod completely, I am unable to connect despite both the server and client having the updated modlist. The error I am seeing is like this one https://gist.github.com/Ibirtem/0013a5c0df160712c4c3b43b946eb87d
In 1.15.2 I will get a warning when loading the world that the blocks are missing and I have to run /fml confirm to load the world, but in 1.16.1 there's no such confirm message.
Making a new world with the same modlist will not have any issues