"Communion" was re-released (after Brooke Shields became famous in "Pretty Baby") in its original uncut form as "Alice, Sweet Alice" in 1978 and then in a cut form as "Holy Terror" in 1981 (after the Brooke Shields' hit "The Blue Lagoon").
The UK cinema version was uncut but the 1998 Tartan video version was cut by 3 seconds to remove a brief shot of a squirming kitten being swung at an attacker (the edit was later extended to 8 secs for the 2003 release). These were considered to fall foul of UK legislation which forbids actual animal cruelty to be depicted in films. The cut was waived for the 2014 88 Films DVD release.
The Brazilian release of the film is fully uncut, but has different music in the opening credits.
The Arrow blu ray release replaces a shot of Father Tom, after getting stabbed in the neck. In previous versions, they use a shot of him stumbling to the camera holding his neck. This alternate shot shows him holding his neck, spitting blood.
The DVD edition has a few other differences in sound between the original 1980's video release. The new version has several seconds of missing soundtrack music and dialogue, while the original release has dramatic music and dialogue during the same scenes.