Along with the Witchwood expansion, tomorrow kicks off the Year of the Raven, rotating the cards available for play in standard formats. It also brings in a new Druid hero, updates to the game’s daily quests, and a number of new card backs that you can earn for various challenges. So you still have to wait just a little bit longer to really get in on the card-slinging fun, but at least you won’t have to wait for a patch tomorrow.
Source: Official Site