Blizzard wants to celebrate StarCraft II's 10th anniversary by publicly testing an anniversary update. It offers new campaign achievements for every mission in the base game and its three expansions. The game will also let players create custom campaigns, which has helped keep its fans. The developer takes in some elements from Warcraft III's game editor to make it easier to use StarCraft II's map editor.
StarCraft II is also getting a new transitioning lobby, allowing players to move quickly between two maps in multiplayer. There is also a new "Campaign" subsection in the game's variants menu. If some of these features seem familiar to you, Blizzard released a lot of these changes with update 4.13's public testing round last Tuesday.
Source: The Verge