The Muji CPD has gone through 4 versions since it’s inception in 1999. The CPD-1 was solely a compact disc player. It is unclear what was updated from the original with the CPD-2.

The CPD-3 added an FM Radio, remote and the ability to play CD-R and CD-RW discs that contain MP3 or WMA files. It is unclear what improvements went into the CPD-4.