Put a check for ACL on mobwrite action.
Will request.user.may still be working with ACL Middleware?
Reported about caching API using Page object instead of Item. Made mobwrite worker use item's arena for caching, as it is more correct.
Studied how locking items works on 1.8 and 1.9. Some doubts about how to do it properly on 2.0, and if it should be done.