This is considered an experimental feature so use at your own risk but if there any issues contact AltSpace support.

Now when you edit a world and select the advanced options for your world at the very bottom you will now have the option to move your world to another universe.

This feature is very welcomed as this was common for some of the builders who have been here for years and have had to work with a messy organisation of their worlds. I did a test myself to make sure that stats were carried across as those metrics are valuable.

Note: If you are that paranoid about doing this step you can take screenshots of your world stats before you attempt this so that it can be corrected if this info for any reason is wiped. I did a test myself, there were no issues.

I tested the feature myself on a test world that had 5 joins and all stats successfully got moved across.