Oddly, the Windows Phone 8.1 update seems to be losing steam. The rollout essentially began at the beginning of August, and had reached 24.4% of devices in the first month. In the month since, it has only been able to get up to 39.1%. Even so, in October WP 8.1 is expected to surpass Windows Phone 8.0, which is currently down to 45.7% of the market. Impressively (or sadly), Windows Phone 7 is still holding strong at 15.2%. This is all according to data gathered by AdDuplex.
The other part of the data is what amounts to the same-as-always for Windows Phone, which is that Nokia devices are absolutely dominating the ecosystem, and to be accurate, it is really the low-end Nokias. The Nokia 520 is by far the most popular phone around the world at 30.6% of devices, while here in the U.S., the Nokia 520 and 521 combine to make up 46.2% of Windows Phones in the wild.