This deleted my 1 hour of time
and bashed my elbow against the radiator
MCL-15725
1.16.4 to 1.15.2 bad map converter
Resolved
Invalid
0
MCL-15725
This deleted my 1 hour of time
and bashed my elbow against the radiator
I feel sorry for your radiator.
As new versions of Minecraft are released, new things are added. If you downgrade Minecraft you risk corrupting your map, as older versions can't understand the new things.
You are warned about this when loading a map, so there is no bug to be fixed here.