The latest tracking stats for Windows Phone have been released by advertising network AdDuplex, which monitors usage across its network to create a detailed monthly breakdown of Microsoft's mobile ecosystem. Each month, the reports capture a snapshot of worldwide usage across one 24-hour period - in this case, January 22, 2016.
The latest data show that Windows 10 Mobile has continued to grow relative to other versions of the OS. In recent months, this has been largely attributed to an increase in the number of users installing Insider Preview builds of the OS, but as in December, it appears that Windows 10 Mobile's latest increased usage has been boosted by new devices.
However, it's worth noting that despite the launch of new Windows 10 Mobile handsets in multiple markets in recent weeks, the growth of the new OS this month is actually smaller than in previous months. It grew from 5.7% in October to 7% in November (up 1.3%), and then to 8.8% in December (up 1.8%). But its latest increase to 9.5% this month (up 0.7%) is its smallest for some time.
Only a handful of devices running the new OS are currently on sale, and despite Microsoft's plans to begin official upgrades from Windows Phone 8.1 in December, and again in January, it now appears that Windows 10 Mobile won't start rolling out until February.
4.3% of active devices around the world are still running the ancient Windows Phone 7.x; those handsets were unable to upgrade to newer versions of the OS, but evidently, many of them are still in use.
AdDuplex acknowledged a minor reporting error in last month's dataset, as it incorrectly grouped devices identified as 'MicrosoftMDG' as part of the 'Other' group of manufacturers. However, the impact of this was negligible since Microsoft/Nokia devices still account for an astonishing 97% of all Windows handsets in use - a clear indication that Microsoft's efforts to boost the platform by bringing in new hardware partners have been less than successful.
Among the roughly 3% of handsets in use from other manufacturers, HTC (1.21%) and Samsung (0.59%) are the most widely used, but BLU Products (0.27%) has just grabbed fourth place from Huawei (0.26%) for the first time.
Globally, there's been no change since December in the top eight most widely-used Windows handsets worldwide, although many of these devices dipped in usage compared with last month. Once again, the ageing Lumia 520 dropped month-on-month, from 14% to 12.9%, but the newer Lumia 535 increased very slightly from 11.4% to 11.7%.
The biggest gain was for Microsoft's impressive Lumia 640, rising from 5.3% of active devices to 6.3% over the last month. Its larger sibling, the Lumia 640 XL, also saw modest gains worldwide, and with 3.3%, it managed to push the much older Lumia 920 into tenth place overall. There are some indications that Microsoft has recently begun clearing stocks of the relatively new Lumia 640 XL, although this development occurred after the latest platform figures were compiled by AdDuplex.
In the United States, the Lumia 635 is still by far the most widely used Windows phone, dipping only very slightly from 31.3% in December to 30.9% this month. The newer Lumia 640 is still gaining in second place, up from 16.5% to 18.2% in recent weeks.
In third place, the Lumia 521 dropped 0.8% to 5.2% this month, but the rest of the top-ten is relatively unchanged, although the entry-level Lumia 435 did jump two places into fifth, thanks to a modest increase of 0.3% over last month.
The last time AdDuplex took a closer look at the top devices in use in Germany was back in November, when the Lumia 630 was in top place with 14.1% - and it's still leading the way this month, with only a small drop to 13.5%.
But the Lumia 640 has increased its share in that time from 9.4% to 10.6%, overtaking the flagship-class Lumia 930 (down from 9.8% to 8.9%) into second place.
In Italy, which has been one of Windows Phone's strongest markets, all but one of the top ten most-used handsets are entry-level or mid-range. As in other markets, older low-cost devices are slowly being replaced by newer ones; both the Lumia 640 and 640 XL have seen sizeable growth there in recent weeks, gradually nudging out older and more premium handsets like the Lumia 820 and 920.
You can check out a deeper overview of this month's AdDuplex report here, including a detailed breakdown of handset usage in Poland, Indonesia and Argentina. AdDuplex will publish its full monthly report tomorrow on its website.