You need to delete old config in order to update it.
Changelog:
- Complete rewrite of the code (see GitHub)
- Fix a bug that shows the same ping of the player
- Added the possibility to check the ping of another player via /ping playername
- New permission system (see "overview" page)
- New fully-configurable config file
- Added /pingreload command with proper permission.
- Added plugin metrics.

BungeePing - Check your/other players ping 2.0
Want to see your in-game ping? With this BungeeCord plugin you can do this by typing /ping