he fourth and final season of the television series Hannah Montana began airing on Disney Channel on July 11, 2010. Production of the season began on January 18, 2010, and ended on May 14, 2010. It is the only season of the series that was filmed in high definition. Also, in this season, Mitchel Musso's character Oliver Oken becomes a recurring character, and is no longer in the main cast. In the season, the Stewarts and Lilly move to a ranch in Malibu. Later in the season, Miley finally reveals to the whole world that she is Hannah Montana. The season ended on January 16, 2011 and May 27, 2011.
The fourth and final season of the series was released on DVD on March 8, 2011.Overview from themoviedb.org