Blizzard updated their World of Warcraft Beta Build Config on their Blizzard's CDN version file:
http://us.patch.battle.net:1119/wow_beta/versions
Last Legion Beta Build 22995 (WOW-22995patch7.1.0_Beta) was back in 2016-11-08 08:08:38 and today Blizzard updated their Version file that included new Beta Build Config for Beta Build 24758 (WOW-24758patch7.3.0_Beta).
Between 2016-11-08 (the date of the opening of Trial of Valor) and 2017-08-04 Blizzard never publicly released an Beta Build.
No details on the expansion have been revealed, but there's speculation it could be themed around Kul Tiras based on a datamined quest set. This speculation was further fueled by Jaina Proudmoore represented on the official Warcraft BlizzCon art.
When do you think we'll learn more about the expansion? BlizzCon or Gamescom 2017?
Source: http://www.wowhead.com/news=269965/u...a-build-config