World of Warcraft Classic is an official vanilla server
https://www.polygon.com/2017/11/3/16603922/world-of-warcraft-classic-announced-trailer-wow-blizzcon-2017
Blizzard Entertainment announced that World of Warcraft will receive an official classic-style “vanilla” server. The news comes from the opening ceremony of this year’s BlizzCon event.
World of Warcraft Classic is Blizzard’s response to fans who have long begged for a server based on the original version of World of Warcraft.