The Inside Adwords Crew have announced that the proposed quality score update has been rolled out today, expecting to last up to 3 or 4 days until complete. The article confirms -

Today, we began rolling out improvements to the Quality Score algorithm, which will update the Quality Score for keywords in your account over the next 3 to 4 days.

As I mentioned last week, the goal of this change is to improve the quality of ads that we serve to our users by making it easier for high quality ads to enter the auction while also discouraging low quality ads. In addition, this change improves our ability to set minimum bids for keywords where we have limited data. As a result, you may see the minimum bid for your keywords increase or decrease based on the updated algorithm.