https://wccftech.com/battle-for-azeroth-patch-8-1-download/

Blizzard has rolled out the first batch of Battle for Azeroth Patch 8.1 Tides of Vengeance data to the World of Warcraft Client background downloader.

Battle for Azeroth Patch 8.1 is currently live on the Public Test Realm (PTR) and will be released on the live servers next week. Ahead of this release, Blizzard has now pushed out the first batch of data for Battle for Azeroth’s first major content update.