Hello

I just updated to 1.21 and wanted to import the json with all the tracked items from my 1.20 world. But when i copy paste the json from 1.20 in the same world for 1.21 and I save it.
When i then open it again the json is correctly loaded with the stuff from 1.20 but when i then open my world it automatically resets it to the 1.21 items already saved (like 1 chest so i get the json).
Is there a way to fix it or am I just stupid?