I have improved and optimized the versions of new worlds in new versions.
Fixed the problem when a world was generated sometimes structures were created.
I have fixed when a world is imported and the server is turned off it
disappeared (Now it doesn't do it anymore and the main worlds appear).

And much more

It is no longer necessary to use the Multiverse-Core plugin, now the plugin is able to create, delete, import.etc many on the server
(IMPORTANT: this plugin only creates empty worlds)

Now you can activate or deactivate gamerules in a faster way.

plugin optimization and internal improvements.