World of Warcraft's sixth expansion already in the works

World of Warcraft's fifth expansion Warlords of Draenor was only unveiled at BlizzCon this weekend, but the one after that is already on the go.

Speaking to Polygon, Blizzard's Mike Morhaime confirmed the sixth expansion is already in the works.

"We've already started working on the expansion after [Warlords of Draenor]," he said.

"We've never done that in the past. We've been doing one expansion at a time, sort of a very linear content creation model, and we've looked at ways that we can parallelize that. So that while we're working on this expansion we're looking at the new one."

World of Warcraft produced just four expansion pakcs in tis first eight years. Morhaime said Blizzard plans to release expansions more rapidly in the future, in order to keep current players engaged and entice returning players.

"It's going to be on us and our development team to continually look at ways to evolve the game and keep it relevant, and look for new ways of maintaining engagement within the game. We view expansions as a huge opportunity to do that," he said.

"We recognize that we need to release them on a faster cadence than we have in the past. So we're investing in the team and our resources to enable us to do that."

According to recent Activision Blizzard financials, following the inevitable spike at release of the fourth expansion, Mists of Pandaria, World of Warcraft noted a significant subscriber dip - down to 7.7 million.