The Base Power for the move Knock Off is stated as 55 when it's actually 65 in X and Y.
I have many a time disappointed myself when trying to fit this move onto a technician user only to find it doesn't get a boost ... :'(
OK this has been fixed.
Although I haven't managed to find a straight answer on what happens with Knock Off vs a Pokemon with Mega Stone. Showdown's description says Mega Stones cannot be knocked off but the code doesn't include that. Bulbapedia says nothing about it.