Bring your world.

1. 1

   Zip the world.

   Find the folder with level.dat in it. For a single-player world, pick it in Minecraft, then Edit, then Open World Folder. Zip that folder.

2. 2

   Stop the server.

   It rewrites its world as it runs, so stop it before you swap anything. Take a backup too, if you might want the old world back.

3. 3

   Upload and unpack.

   In the Files tab, press Upload and pick the zip. Then open its menu and choose Unpack here. Delete the zip once that's done, since it would go into every backup.

4. 4

   Swap the folders.

   Delete the folder called world and rename yours to world. If there are folders called world_nether and world_the_end beside it, delete those too, or the server keeps its old Nether and End.

5. 5

   Start it.

   Your world is the one friends join from now on.

Good to know.

• The server has to be on the world's version or a newer one. Change it in Settings if you need to.
• On the newest Paper and Purpur, the first start warns that it's converting the world and waits 30 seconds. Let it carry on. You can watch it in the Console.
• You arrive at the world's spawn with empty pockets, because a single-player world keeps your own things in a file the server doesn't read.

A zip can be 4 GB at most. For anything bigger, write to support@octocarbon.com.