Minecraft – way to choose which biomes DON’T spawn

In past updates, biome changes have been retroactive. I logged into my original singleplayer world recently to find it was now a snow biome.

You can use a map editor (such as MCEdit) or a game mod (such as Bukkit WorldEdit plugin) to delete the chunks you haven't built anything in. When you explore them again, they'll regenerate using the most up-to-date method.

If you really want all the latest terrain everywhere, use MCEdit to copy your base and export it as a schematic. Write down the world seed. Start a new world in Minecraft using the same seed, then exit Minecraft and use MCEdit to import your old base into the new world.

As of now, underneath the world's name, original name, an last time played, it tells you the base gamemode, if there are cheats or not, and the version.