New Zealand Cricket has added a signal for an umpire requesting a review. It's been brought in to clarify the difference between a referral - where the third umpire is required to make a decision - and a review, where the on-field umpire simply wants a hand.
The signal will be the umpire crossing his wrists with his hands above the head before contacting the third umpire.
There's no truth to the rumour that a signal will be introduced to indicate a batsman should have walked when he nicked it - a single raised middle-finger.