High Quality Content by WIKIPEDIA articles! The Umpire Decision Review System (abbreviated as UDRS or DRS) is a technology based system used in the sport of cricket. The system was first introduced in Test Cricket for the sole purpose of reviewing the controversial decisions made by the on-field umpires in the case of a batsman being dismissed or not. The new review system was officially launched by International Cricket Council on 24 November 2009 during the first Test match between New Zealand and Pakistan at the University Oval in Dunedin. It was first used in One Day Internationals in January 2011, during England`s tour of Australia. The ICC had made the UDRS mandatory in all international matches but it later decided to end the mandatory use of DRS and now it will be up to both the teams to mutually agree on DRS use. However, the ICC`s executive board made it clear that the DRS would still be part of all ICC events and that they support the use of technology and would continue to work on its development.