The album was released on a double CD in March 2004 as a pre-release version available only via internet from the TDI site and selected mail order companies. Similar to Inferno, the official store release was issued a short time later, featuring slightly different cover artwork, including a barcode field that is missing on the pre-release copies. Furthermore the official release has a slightly different sound mix.
The music of Purgatorio is quite similar to that of Inferno but features more instrumental parts and has some stronger, sometimes even catchy melodies.
In January 2007 this release became available as MP3 download at the Tangerine Dream Download Shop.
In March 2009 the album was re-released with different cover design as part of an extensive digipack series (consisting of a total of more than 60 CD and DVD releases) by the Germany based Membran record label.
2CD: TDI CD036; first release without barcodes
2CD: TDI CD036; second release with barcodes; different booklet; slightly different sound mix
2CD: 232656; digipack
2007: Tangerine Dream Download Shop
Download: complete release or individual tracks as MP3