Our servers now run Java 16 enabling the use of latest snapshot release of Minecraft 1.17 Caves and Cliffs update. (21W19A Snapshot)
Note that some older versions of minecraft builds like Forge modpacks may not be compatible with Java 16, so we recommend that you continue to use the older versions.
You can change Java versions any time from Control Panel --> Settings --> Express Settings --> Java Version section of the control panel