In this instance, the game's ranked play league percentages have been altered to better reflect player skill levels, according to a post on the game's official website.
The changes deal mostly with the Bronze league, where beginning players would spend a long time waiting to be promoted.
In the original StarCraft 2, the Bronze, Silver and Gold tiers are equally distributed with 20 percent of players each.
Blizzard commented the lowest tier, Bronze, "encompassed a skill range that was too broad to be meaningful" and "gold was too narrow."
"As a result, the lowest ranked players in Bronze often tended to be far removed from the skill level of those at the top, or even the middle of the league," Blizzard community manager Spyrian wrote. "As such, we're going to alter the population percentages for Bronze, Silver, and Gold leagues in order to equalize these skill gaps, and help each feel more meaningful."
Bronze will now account for 8 percent, Silver 20 percent and Gold 32 percent in the new "Heart of the Swarm" expansion, released today.
The remaining 40 percent, which encompasses ranks from Platinum to Grand Master, will be unaffected by the changes.
StarCraft 2: Heart of the Swarm, the game's Zerg-based campaign, saw a midnight release last night at Melbourne's Federation Square that included some show matches, Q&A panels featuring Game Director Dustin Browder and Aussie 3D Artist Luke Mancini, as well as a showcase of some some short films, parodies, and behind the scenes videos.
Pictured below are the multiplayer league changes, with the original arrangement followed by the change.
Heart of the Swarm: