"Starting on November 14th, StarCraft 2 Wings of Liberty can be played for free. Player can access all content including singleplayer campaign and Co-op Commander Access to competitive multiplayer mode will also be free," Blizzard wrote in an official announcement.
While the expansion Legacy of Void and Heart of Swarm can still be obtained for each US $ 15. Blizzard will also feature Premium Upgrade feature to players who want to access additional content such as skins and other Co-op Commander.
This feature can be accessed for free when players are still below level 5. Afterwards, players have to pay if you want to use the feature.
Blizzard's decision this time is most likely a reaction to the number of players and the popularity of StarCraft 2 which continues to decline and lost by other competitive games, including Overwatch.
With free access to StarCraft 2, Blizzard hopes to boost its popularity until it has a strong esport ecosystem.