How to restore a downgraded server?

[JKLiu]

Recently, I have upgraded my server and it seems like it didn't start up after updated, so I downgraded to the orginal version of the server. However, the world save has disappeared and apparently it resets the world save. Is there any way that to restore the world save?

[_Tarna_]

Check the other worlds on your server to make sure it just didn't put you in a different world from the real one. Also note that once you upgrade to a server version, you won't be able to downgrade without using some sort of backup or a third party software.