Although the full launch remains scheduled for August 27, the WoW Classic servers will go live tomorrow. This is not another beta test, but a chance for those with an active subscription or game time on their WoW account to reserve their character names and select the realm where they want to play.
https://www.notebookcheck.net/WoW-Classic-servers-will-go-live-tomorrow-for-name-reservation-and-realm-selection.430082.0.html