Dance Dance Revolution 4thMix Plus is an upgrade of 4thMix, released on December 28, 2000. It adds fourteen new songs not seen in any previous DDR version. Several older songs have received new Maniac step sets, with the old steps being moved to "Maniac-S" (for Single) or "Maniac-D" (for Double). The new steps are generally much harder than before, and are used as the default Maniac steps in Dance Dance Revolution 5thMix. The old step sets have been restored for songs included in DDRMAX2 Dance Dance Revolution 7thMix, and certain 4thMix Plus steps return as Challenge steps in Dance Dance Revolution Extreme. An all music mode feature is included for Dance Dance Revolution 4thMix Plus where players have access to all songs in the game instead of picking music genres