After the remake of the Canadian cult-slasher "Black Christmas" was shown in American movie theatres with an R-Rating, it was released on DVD in its home country both as an R-Rated version and as an Unrated version. The IMDB lists 7 scenes/elements, which have been added in the Unrated version. Also, there are rumors, that the R-Rated DVD, which is being sold in the USA and Canada, is different from the theatrical version with the same rating.
A "European Version" containing more visibly brutal murder-scenes and an alternative ending is also known.

Several sources confirm that the version on the UK DVD is special in some ways. And it is. The comparison between the R-Rated and the English version shows that a few details only concerning seconds are missing in both versions, for Michelle's death a completely different scene was used and the two versions have a different ending, too.
Additionally to the compared version the movie with the original US-ending can be found as bonus feature on the UK DVD from Pathe!. What was compared is the "real" UK-Version which is the main movie in the menu. A comparison frame by frame showed that they are not different except for the ending.

This is a comparison between the UK DVD from Pathe! (BBFC 15) and the German DVD from Concorde Home Entertainment ("Keine Jugendfreigabe") (which is identical to the R-Rated). All in all 11,68 seconds are missing in the R-Rated with a total of 5 cuts.
All in all 3,68 seconds are missing in the UK version with a total of 1 cut.
At 2 parts alternative footage has been used. The resulting time time differences have not been considered in those times.

Running time of the UK DVD excluding end titles: 1:14.46 min
Running time of the German DVD excluding end titles: 1:17.32 min
The information about the running time is from both versions, following the scheme German / UK.

0.00 - Cut in the R-Rated
The black frame at the beginning is longer in the UK-Version.
0,4 sec

57.42 / 57.43 - Cut in the R-Rated
Melissa can be seen in an additional shot, Billy is sneaking up to her. The following shot of Melissa is three frames longer in the R-Rated.
2,4 sec

57.46 / 57.50 - Alternative footage
Melissa's death is completely different in the two versions:

UK: Melissa is already falling to the ground, Agnes tears out one of her eyes through the garbage bag and bites into it with joy. She sticks a finger into the eye hole and drags Melissa who is still alive and floundering out of the frame. (15,24 sec)

R-Rated: Melissa and Agnes are fighting a little longer then Melissa can break free and flees into a room. She tries to escape through a window but does not manage to open one of them. Agnes grabs an ice-skate and throws it at Melissa which leads to a fatal head wound which is presented to the audience in a close up afterwards. (33,84 sec)

+18,6 sec

1:01.24 / 1:01.09 - Cut in the R-Rated
(Leigh: „Until I see that she’s dead, she is alive.”)
Kyle: „They’re not!“
Leigh: „They are!“
1,76 sec

1:01.32 / 1:01.19 - Cut in the R-Rated
Leigh can be seen longer before she starts talking.
1,2 sec

1:01.37 / 1:01.25 - Cut in the R-Rated
Kelli: „If you don’t think you owe me, you fucking owe Meghan at least this!”
5,92 sec

1:04.34 / 1:04.27 - Cut in the UK-Version
Agnes biting into an eye with joy in a close up is missing in the UK-Version.
+3,68 sec

1:09.14 / 1:09.04 - Alternative footage
The two versions have a completely different ending.

R-Rated: A reporter talks a bit about the things which happened in the movie, then we see an over-motivated pathologist moving new corpses into the pathology, irritatedly having a conversation on the phone, fixing himself a drink and trying to open a candy cane. He notices something strange and checks the body bags suddenly Billy jumps at him and kills him. Kelli and Leigh have a short talk then a nurse comes to take Kelli with her and Leigh investigates on some strange noises. When she returns to the room she thinks Kelli is back but the blond hair really belongs to Agnes. She kills Leigh and when Kelli returns to the room she notices the bloody watch and wants to escape but is being attacked by Agnes anyway. Here, too, a defibrillator saves lifes – Kelli's. She kills Agnes with it and then she shortly has to deal with Billy until she throws him over a balustrade skewering him on a Christmas tree. (497,88 sec)

UK: The scene starts with the dialogue including the giving away of the watch which is shown in the R-Rated, too. The doctors try to reanimate "Billy the briquette" and the body from Agnes’ body bag is identified as Claire. Then the scene of Leigh seeing "Kelli" in her bed and getting a nasty surprise. Billy is ultimately dead and Kelli discovers the bloody watch. Then the already known unit of scenes with Agnes, the defibrillator and a lot of barbecue meat but not followed by Billy's appearance but by Kelli crouching on a wall. Cut and then a scene of Kelli's parents picking her up from the hospital. The movie ends with a shot of a "Peace on Earth"-sign on a door.(342,24 sec)

155,64 sec difference