Bukkit

Reduced CPU usage when checking whether explosions should break blocks.
MCore 6.8.1 is soon released which should further decrease lag from explosions.

Remember that in the version change: 2.0.x → 2.1.0
Offline explosion protection were added in per default for all Factions in this update. As a side effect the special factions Wilderness, WarZone and SafeZone will get that default value if you are updating. You should manually set offline explosions to false for these special factions otherwise explosions will not work properly there. Run:

1. /f flag wilderness offlineexplosions true
2. /f flag safezone offlineexplosions true
3. /f flag warzone offlineexplosions true

http://www.massivecraft.com/factions-owner#update