Petit Ferret released a trial version of Popotan for download on November 25, 2002 and released the full PC version on one CD-ROM the following December 13. To increase pre-order sales, Ferret packaged the initial CD-ROM release of Popotan with a special maxi single CD of Under17's theme songs. The firm then released a fan disc on July 11, 2003, titled . The disc includes several character-based mini-games (including the original's "Magical Girl Mii" mini-game), new storyline content and routes based around Mii and Nono, a separate music CD containing background music from the original game, themed computer wallpaper, and desktop accessories. Some of the items must be unlocked. The fan disc preceded a re-release of the main game as Popotan Po! on August 1, 2003, as a DVD-ROM with game enhancements; it would be Petit Ferret's last official release. WellMADE produced a PS2 port named Oshiete! Popotan, released March 11, 2004. Scenes in the port were changed or removed to comply with Sony's ban on sexual content, but the release still warranted CERO 18 rating. Later, after the CERO revised its rating system, it was given a CERO D rating. WellMADE tried to compensate for their absence with graphics and gameplay improvements. WellMADE enticed buyers of the port with a bonus themed calling card, reversible poster, and music CD. WellMADE also released two free spinoff games in December 2003 and March 2004, collectively named and featuring Unagi as the heroine. WellMADE designed the games to be humorous and fun; the second allows Unagi to transform into her humanoid form after a certain point in the story.
