SetNPCBlackboard() changed behavior when passing nil
In order to allow unsetting keys on the blackboard, the behavior when calling SetNPCBlackboard(entity, key, nil) was changed. Before 4.10 Beta 5 this was a noop change. As of 4.10 Beta 5 the call will now clear the value of the passed key. See - XRUIMOD-138Getting issue details... STATUS for details.
We don't expect any issues out of this, since we assume that anybody actually calling the function that way expected the value to be reset. Feel free to leave us a comment here, if that behavior change causes problems for you.