 At CES 2007, Warner proposed Total Hi Def—a hybrid disc containing Blu-ray on one side and HD DVD on the other, but it was never released.On June 28, 2007, Twentieth Century Fox cited Blu-ray Disc's adoption of the BD+ anticopying system as key to their decision to support the Blu-ray Disc format.On January 4, 2008, a day before CES 2008, Warner Bros. (the only major studio still releasing movies in both HD DVD and Blu-ray Disc format) announced that it would release only in Blu-ray Disc after May 2008.