Nokia confirmed today that it sold 8.2 million Lumia Windows Phone devices in the fourth quarter of 2013. That figure represents a decline of 600,000 from the third quarter in which Nokia sold 8.8 million Lumia handsets. The fall comes on the cusp of the sale of the majority of Nokia’s hardware assets to Microsoft, meaning that the slip is more Microsoft’s problem than Nokia’s. But it is a weak indicator for the larger Windows Phone platform that was showing signs of gathering momentum.