Minecraft same world with the same seed with a new version?

Maybe there are minecraft experts here: With new Minecraft versions, e.g. New biomes, a seed from a very old version creates a different world than the same seed in the latest version. Does anyone know in which versions such a "generator change" took place? I currently have a 1.12.2 world and would like to update it sometime without cuts being made to parts of the world that are not yet loaded because the world is now calculated differently.

I know that the complete generation code was rewritten in 1.13, so there will be very different results.