I created this plugin to fast convert players files from 1.7.5 to 1.7.9 UUID style on my offline mode server.
How to use:
Plugin works on spigot 1.7.5
- Stop your server
- Delete all plugins on your server (or just rename plugins to plugins2)
- Put UUIDConvertTool.jar in plugins
- Create directory playerdata in your main world directory
- Start server, look on console
- Stop server when last nickname converted.
- Delete whitelist.txt, ops.txt banned-players.txt
- Upload your plugins again (or just rename plugins2 to plugins)
- Change spigot to 1.7.9
- Start server & Have fun!
REMEMBER TO DO BACKUPS!

UUIDConvertTool (offline mode) 1.0.0
Simple and fast UUID converter for offline mode servers