Released 2024-12-03
Minecraft 1.21.4: Java 21
1.21.4 is a recent release in the 1.21 line, on Java 21 like the rest of it. Plugin server software tracks these releases quickly; mod ecosystems take considerably longer.
Java version required
21or newer
Older Java will refuse to start. Much newer Java usually works, but the server software is what decides that, not Minecraft.
Availability
Paper is available for 1.21.4
It accepts Bukkit / Spigot / Paper plugins.
Will what I downloaded work?
Mods and plugins are different things that both arrive as a .jar file. Putting the wrong one in usually produces no error at all — the server starts, and the content simply is not there.
running on Paper
No. Forge produces mods and Paper runs plugins — they are different systems that happen to share a file extension. Nothing will load, and nothing will warn you.
What to watch for on this version
The gap between plugin and mod availability is the thing to plan around. Paper and Purpur typically have builds within days of a Minecraft release, so a plugin server can follow the latest version closely. A modded server cannot — mods lag by months, and a pack will not move until every mod in it has. If you are running mods, pin the version and stop chasing.
Where this sits in the Java timeline
- Java 81.7 through 1.16.5
- Java 161.17 and 1.17.1
- Java 171.18 through 1.20.4
- Java 211.20.5 and everything after