cant update my multiplayer server world to newest snapshot

when i change my server type to 21w19a and then try to start up the world again it displayes this error message in the console:

Error: LinkageError occurred while loading main class net.minecraft.server.Main

java.lang.UnsupportedClassVersionError: net/minecraft/server/Main has been compiled by a more recent version of the Java Runtime (class file version 60.0), this version of the Java Runtime only recognizes class file versions up to 55.0

what can i do to fix this