All versions

What Java version does Minecraft 1.21.6 need?

Java 21

Minecraft 1.21.6 was released on 2025-06-17. Mojang's version file lists Java 21 for it, for both the game and a server.

FabricYes
ForgeYes
NeoForgeYes
Top mods listing 1.21.6299 of 500

See which Java you have:

java -version

Download Java 21 from Adoptium