If you want to preserve an older world you created without risking that world experiencing corruption or update problems when you move to a newer version of Minecraft, you’ll need to lock the profile to the older version.If you play online most multiplayer servers typically don’t immediately update to the most current version as it is a huge headache for server owners to perform major updates.
Check the first option if you want to enable experimental releases and then check the next two if you want to play around with the very old Beta and Alpha releases from circa 2010-2011.
When you check off the “Enable experimental development builds” box you’ll get this warning: That’s exactly why we’re using the profile system and keeping our worlds separated in different game data directories.
That’s pretty much a recipe for disaster as you can corrupt your worlds and cause other problems by opening them with the wrong version of Minecraft.
To easily prevent that, we’re going to create some profiles to divide up the version numbers and change the default game data directory for each profile.
The first two, and most easy to use, are Vanilla Minecraft and Bukkit or Spigot.