This December Microsoft will relax its Windows Store restrictions so some games rated 18 in Europe may be sold within.

The current limit for games in the store is Pan European Game Information (PEGI) 16, which was thought to be the equivalent to the United States’ Entertainment Software Rating Board (ESRB) Mature rating.

However, many ESRB Mature games are rated PEGI 18, including Call of Duty: Modern Warfare, Skyrim, Assassin's Creed, Mass Effect, and Halo.

"[PEGI 18] basically ends up disqualifying games that would be ESRB Mature," said Windows corporate VP of web services Antoine Leblond.

The December time frame would “give developers a heads up that that’s where we’re going, so they can have the peace of mind around developing the kinds of games that will have those ratings,” he added.

“We want the world of desktop apps to keep existing [outside of the Windows Store]. There’s no reason to get in the way of that. Valve can keep being Valve.”

PEGI describes its 18 rating thus:

“The adult classification is applied when the level of violence reaches a stage where it becomes a depiction of gross violence and/or includes elements of specific types of violence. Gross violence is the most difficult to define since it can be very subjective in many cases, but in general terms it can be classed as the depictions of violence that would make the viewer feel a sense of revulsion.”