There is no way to turn off mob griefing and it used to be "/gamerule doMobGriefing (True/false)" and you also can't change gamemode by number "/gamemode (1/2/3)". Please fix this.
MC-141528
Commands are broken for mob griefing
Resolved
Duplicate
0
(Unassigned)
Unconfirmed
Minecraft 18w48a, Minecraft 18w48b, Minecraft 18w49a, Minecraft 18w50a
Retrieved
See MC-73225 and MC-127443.