The most important thing you should note is that there are no official beta keys. Blizzard opens the gates to their betas by granting access to your account — not sending you a beta key. If you’re in the beta, you’ll be able to download and play the WoW Classic client from your Battle.net launcher. If not, you aren’t in the beta. It’s easy to be tricked into thinking you’ll get a beta key from an email that looks like it’s from an official Blizzard address, but don’t believe their lies — they’re all fake.
Kaivax, a WoW forum community manager, revealed that WoW Classic's class design, battleground mechanics and stats on existing items will be set to their 1.12 state, despite the game releasing content that expands beyond that. This removes "progressive itemization," so if the stats on a specific piece of equipment was changed during the original updates, that won't take effect in this version.
To celebrate World of Warcraft’s 15th anniversary, Blizzard is planning to release an authentic recreation of its early days with WoW Classic. Players will be able to explore Azeroth as it originally was before the release of WoW’s many expansion sets. Initially it’ll feature encounters like Molten Core, Onyxia and Maraudon at launch and will see more content rolled out as the game goes on (such as Alterac Valley, the Ahn’Qiraj War Effort and Naxxramas). It’s not just the world that’s reverting to its classic form either – the combat mechanics, skill trees and character models will be as they were in the original too.