minecraft beta question

If you start playing with the beta- or any older version- of Minecraft, and update it to a newer version, your world is pretty much fine. If you go to unexplored chunks in the updated version in the same world, the only potential issue is that you might see a noticeable wall of terrain generation differences depending on the versions you jump to and from. You'll also notice other differences between the versions, but beside that, there aren't any real issues. Now days (in Java edition at least) you'll get this nice message to warn you.