The key "lastOpenedWithVersion" in the level.dat of the world is written correctly when the level.dat is created the first time. It is then not modified from that point on.

The name would suggest that it would get rewritten each time the world is saved to match the last version number that the world was opened in.

Current behaviour: create world in version number "x", save and close, then open the world in version number "y", save and close, and lastOpenedWithVersion will still say "x"

Expected behaviour: all of the above but lastOpenedWithVersion should say "y"