I've been playing on a very old world likely made in 2013, and last opened in 2014. However, the world takes a very long time to load, and then a very long time to save. If I try to make the world infinite, it crashes almost immediately.

Re-opening the game, it appears at first that the upgrade worked. However, opening up the world that should now be infinite shows that the world is still limited in size.

To make things more confusing, it appears that both versions had invisible blocks that were there before the world conversion.

It doesn't appear there are any differences between the two worlds, (levelname) and (levelname)-Old .