The next beta event will run from June 9 to June 23. We’ll be running two matchups in a row for the first time using the system, allowing us to test the one-up, one-down matching system at scale and validate matchmaking bug fixes. Assuming this test goes according to plan, we aim to run another beta test later this summer that introduces the first version of the long-awaited Alliances system, which allows multiple guilds to combine forces and be placed on a WvW team together.
The beta begins this Friday, June 9 at 11:00 a.m. Pacific Time (UTC-7) for Europe, and at 7:00 p.m. Pacific Time (UTC-7) for North America. To be matchmade with a guild of your choosing, you must select a guild to play with for this beta event prior to 11:59 p.m. Pacific Time (UTC-7) on June 8. To do this, simply open the Guild menu in the game, highlight the guild you’d like to play with in the guild list panel on the left-hand side, and then click the “Set as WvW Guild” button located just below your guild list.
https://www.guildwars2.com/en/news/dev-notes-june-6-wvw-updates-and-world-restructuring-beta-test/