Recently, StarCraft 2 fans were invited to participate in testing update 5.0.15 on a special PTR server.
The developers are making a number of balance adjustments to all factions — Zerg, Protoss, and Terran have received buffs, and in some cases, units have been weakened.
They are also fixing various technical issues and bugs related to game mechanics.
The full description of update 5.0.15 for StarCraft 2 is available at the following link.