Blizzard announced today that World of Warcraft Classic will be set in patch 1.12: Drums of War. In a developer update, Blizzard said it chose patch 1.12 “because it represents the most complete version of the classic experience.”

Players have been debating for months — since the reveal of World of Warcraft Classic last BlizzCon — about what “Classic” truly means. Is it 1.1? Is it the final patch of “vanilla WoW?” What is the true World of Warcraft experience for old-school players? With the announcement today, Blizzard has answered that question.

But Blizzard wants to do more than just recreate WoW 1.12, they want to give a good, modern experience for their players alongside the warts and glory of vanilla.

So we asked ourselves, would it still be possible to deliver an authentic classic experience if we took our modern code, with all its back-end improvements and changes, and used it to process the Patch 1.12 game data? While that might seem counterintuitive, this would inherently include classic systems like skill ranks, old quests and terrain, talents, and so on, while later features like Transmog and Achievements would effectively not exist because they were entirely absent from the data. After weeks of R&D, experimentation, and prototyping, we were confident we could deliver the classic WoW content and gameplay without sacrificing the literally millions of hours put in to back-end development over the past 13 years.

Almost nothing is known about World of Warcraft Classic outside of this recent announcement. For example, we aren’t sure if Classic will ever grow beyond patch 1.12 and move into the Burning Crusade.

It’s also unclear if some of WoW’s less player-friendly systems will remain. For example, Shaman and Paladin classes were Horde and Alliance-specific in vanilla World of Warcraft. Blizzard could change this to appease Paladin Horde players or leave it be to keep the game feeling authentic. We won’t know until closer to launch.

Patch 1.12 was the final patch in World of Warcraft’s vanilla days and was originally released on Aug. 22, 2006. This means players will have access to every vanilla raid and feature up until the Burning Crusade expansion.

We’ll likely learn more about WoW Classic in the coming months and will probably see it in action for the first time at this year’s BlizzCon, which will take place in Anaheim during the first weekend of November.

World of Warcraft Classic is expected to release for Mac and Windows PC.