Translations:Notice to Server Owners/14/en
From DragonMineZ Wiki
Every config file carries a configVersion. When you install a newer DMZ, outdated files are regenerated with the new defaults and your changed values are merged back in (values you never touched take the new defaults). This is expected behavior, not a bug: see How to JSON for exactly how the merge works, and compare with the copy in oldBackup/ if a value looks wrong after an update.