Hi, I've been running a SMP server for a few months now, and I've decided to update the server, but I want to keep the old world. However, when I try to copy over my old world to my new server file, I noticed that all my player data deletes from the world. The files seem to be visually the same between the two worlds, but all my player data is gone.

If anyone knows how to fix this, that would be great!
Many thanks