Rock Band 4 is a 2015 music video game developed and published by Harmonix for the Xbox One and the PlayStation 4. Rock Band 4 allows players to simulate the playing of music across many different decades and genres using instrument controllers that mimic playing lead and bass guitar, drums, and vocals. As the fourth main installment and the seventh major console installment in the Rock Band franchise, it was released on October 6, 2015. Mad Catz, who also developed new instrument controllers for the game, marketed and distributed the title worldwide at launch; Performance Designed Products (PDP) took over manufacturing and distribution by the end of 2016. The game shipped with more than sixty licensed songs; additional songs are available as downloadable content, which includes a library of over 2000 existing songs from prior installments.
Rock Band 4 offers backward compatibility with content and hardware from previous versions of Rock Band within the same console family; wireless guitar and drum controllers from PlayStation 3 and Xbox 360 versions of Rock Band can be used on the PS4 and Xbox One versions (with Xbox One requiring a newly produced USB dongle and PS4 not requiring any new hardware), and DLC songs purchased on prior installments on PS3 and Xbox 360 can be re-downloaded at no extra charge on PS4 and Xbox One in a ported form that supports the game's features. Harmonix plans to release free and paid DLC that will add new features and content to the game over time, in lieu of releasing yearly installments; this includes the addition of support for synchronous online play added on January 25, 2017.