Nucleus released this version on Mar 10, 2018

4.0 MB

This is a bug fix and minor feature release for Nucleus 1.3.x.

Release Notes

If you’re having trouble, visit our Discord channel: https://discord.gg/A9QHG5H

New Features

World UUID migration

Sometimes, you have to delete that pesky level_sponge.dat. Sometimes, you come back to your freshly restarted server and you see that your level_sponge.dat all but deleted itself, leaving nothing more than a “derp” as your only clue that you have to painstakingly go through all your plugin configs one more time.

As you fight back the tears and assign a new UUID for every. one. of. your. worlds, with the occasional bad language and contemplation of why life threw you this curve ball, be assured that us at Nucleus are trying to make that job just that little bit better.

As you may have seen, Nucleus recently gained a handy-dandy world UUID tracker that tells you when things have gone wrong in the world (of the minecraft variety), and can try to repair this. But sometimes, that just doesn’t work. Maybe you’ve just cloned your world and the UUID change is an expected, if not unfortunate side-effect?

Introducing the Nucleus World UUID mapping! Now, in your main.conf, under the core section, this new config option has appeared (with examples)!

    # If you are having issues because a world UUID changed and you were unable to fix it, this allows you to redirect old UUIDs to new ones (or world names). This is a map of old world UUIDs to new world names or new world UUIDs, the following are both valid:
    # "123e4567-e89b-12d3-a456-426655440000"="world"
    # "123e4567-e89b-12d3-a456-426655440000"="1b671a64-40d5-491e-99b0-da01ff1f3341"
    # Other plugins will be able to check this map to perform their own migrations, support for that is up to those plugins.
    world-uuid-migration {

Now, if you have an old world UUID that is now a different UUID (or even world name!), you can add an entry into here in the form



olduuid="new world name"

Nucleus will then update its user and general data files the next time they are loaded to point at the new world. You don’t have to trawl through 10k Nucleus player files, your players can find their homes again, everyone wins!

As an added bonus, any plugin developer that depends on the Nucleus API can also see these mappings. Once the game has started (VERY important, NOT BEFORE), call this line with your current UUID and see if the admin has added a mapping!

(It turns out that when I’m in a really good mood, I write more than I plan to…)

Updated some error messages for kits

Specifically, it won’t send an error message for /kit if you use a subcommand and it’s clear what you tried (and unfortunately failed) to do.


  • Fix Nucleus not working on slightly older SpongeForge builds (including latest recommended) with /world tp.

Known Issues

  • Sometimes, an incorrect custom prefix might be selected. Nucleus uses whatever the permission plugin hands back, check your inheritance with the permissions plugin.

Commit History