Starcraft 2: Heart of the Swarm has no official release window, but the Australian Classification Board has seen enough of the strategy expansion to award it a rating, suggesting it could be almost upon us.
The Classification Board has awarded Heart of the Swarm an M for violence, with a note regarding online experiences.
Publishers occasionally submit games for classification months ahead of release, as they don't need to show the full, complete game - but it usually means things are drawing to a close on the development side. In this case, it may indicate all the campaign material - cutscenes and dialogue - is complete, while Blizzard continues to nail down the nitty-gritties of balancing units, which could take quite a long time.
In one interesting little blip, the version classified by the board is listed as "modified"; that usually means a game has been re-submitted after being refused classification or because the publisher has requested a reassessment. We've asked the Board for clarification of this, but it seems likely to be a clerical error as only one version of the game was ever submitted.
Heart of the Swarm has never been flagged with a release date but Blizzard has begun talking about an upcoming beta.