Assassin’s Creed 4 on PC will release three weeks after the console versions, and according to Ubisoft, the reason PC titles sometimes tend to release later, is due to which system the “master version” was created on.

Speaking with Polygon, Assassin’s Creed 4 lead designer Jean-Sebastien Decant said the team spends the most time on the master version of a game before starting work on the remaining systems.

“It all depends on what is the master version,” Decant said. “If for instance, the [Xbox 360] version was the master version, or the PlayStation 3 version was the master version, then we’d need a little bit more time to adapt it for the PC. But we need to finish that other version first.

“The technology goal we had [for AC4] was for the current-gen. You need to finish one and make sure that it’s clean before you can then finish the others.”

Assassin’s Creed 4: Black Flag lands on PS3 and Xbox 360 October 29 in North America, and November 1 across Europe. The PC version is due on November 19.

The PS4, Wii U and Xbox One versions will be made available on November 22.