Warner Bros. has moved the release date for the latest installment in the Harry Potter series, Harry Potter and the Half-Blood Prince, from November 21st to July 17th, according to Variety. The move is caused by what Warners considers to be a weak Summer '09 slate of films. As of right now the final installment of the series, Harry Potter and the Deathly Hollows (which will be released in two parts), is not going to be affected by the switch.