I and my girlfriend have been playing on a Minecraft world 1.15.2. We want to move to version 1.16.2.
But when we (I) do that, all in-game commands won't work. Like the server/console doesn't register them. But when the commands and typed into the console, they work just fine.
did you try
Yes, no luck.
I have found out, it happens when the old "region" folder and "level.dat" are coming into the new server version.
I fixed it, follwed this guide