Hi
So, I have a little server in version 1.15.2. I tried to upgrade to version 1.16.2 but everything broke. Some blocks were replaced with others, some textures changed or disappeared. One of the persons playing in the server got the nether portal interior replaced with soul sand, and while others could go through, he couldn't.
I do have some mods, but they don't change world generation in any form (Xaero's minimap and Ore Excavation).
I had a backup, so I could repair the server, but I would still like to try.
What's the problem?
How could I fix it?