Unable attack other players and entites in worlds created before 0.15.10

Unable to attack/hit entities in worlds created before 0.15.10. Only affects Pocket Edition.

Affect(s) Devices:

Apple iPad Mini 3rd Generation - iOS 10.0.1 - Version: 0.15.10
Apple iPod Touch 6th Generation - iOS 10.0 Beta 4 - Version: 0.15.10
LG K7 - Android 5.1.1 - Version: 0.16.0
Samsung Galaxy Tab A 8.0 - Android 5.1.1 Version: 0.16.0