In a fairly detailed blog, the World of Warcraft Developers given insight into the status of the Classic project.
The community had long wanted classic World of Warcraft servers. Various fan projects with illegal servers simulated the experience, but could never offer the full program or were closed by Blizzard due to copyright infringements.
Last year on the BlizzCon there was finally the official announcement that Blizzard would tackle World of Warcraft Classic.
World of Warcraft Classic - A huge project
However, the project is more extensive than some might think and the team is writing about it.
Even if some laypeople simply imagine setting up a server, backup of the program code from WoW 1.0 search from the archive and upload and end. Unfortunately, it doesn't work that simple.
“Back then” there was not only a completely different hardware, but the operating systems have since changed from 32 to 64 bits. Not to mention the support of modern graphics cards.
So the team didn't just have to choose the entry point, Patch 1.12: Drums of War, but also bring the program code to today's level. Also, the current programming tools from Blizzard are very different nowadays. For example, the login system or anti-cheater measures look very different today.
Another example will be improved modern Database Structures presented. The methods used to save the spells and their effects are very different today and the team had to find ways to convert this data.
So it's no wonder that Classic server project but takes a long time and yet consumes extensive Blizzard resources. Because where fan projects with minor errors and bugs were excused, other, higher standards apply to Blizzard.
The detailed explanation of the World of Warcraft Classic Team can be found on the blog page.