The latest tracking stats for Windows phones 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, May 16, 2016.
As you might expect, Windows 10 Mobile has increased in usage compared with last month - but only slightly, rising by 1.2% over April, and now accounting for more than 10% of all active Windows handsets. Windows Phone 8.1 remains the largest OS version in use by a massive margin - no doubt due to the fact that Microsoft still hasn't 'pushed' Windows 10 Mobile to most devices that are eligible.
Those whose handsets are on the official list of upgradeable devices must first download an app in order to get the update - but without first receiving an upgrade prompt on their devices, most Windows Phone 8.1 users out there are unlikely to even be aware that Windows 10 Mobile is available to them.
Of those that have installed Windows 10 Mobile on their handsets, almost 15% are running Insider Preview builds of the OS, with over 85% on official 'stable' releases.
And of the total number of Lumia handsets running Windows 10 Mobile, over 77% were upgraded from Windows Phone 8.1, while the remainder are brand new devices from the Lumia x50 series, which shipped with the latest OS onboard.
While that chart applies exclusively to Microsoft's Lumia line, it effectively covers the overwhelming majority of the ecosystem, given that Lumias still make up a shockingly high proportion of all Windows phones.
Indeed, Lumia continues to account for more than 97% of all active Windows handsets, despite Microsoft having convinced dozens of its hardware partners to launch Windows phones over the last two years.
Of the top five manufacturers in the ecosystem, Blu is the newest, making up just 0.26% of active handsets. HTC, Samsung and Huawei haven't launched new Windows handsets for around two years, while all the other manufacturers combined account for less than 1% of active devices, indicating that total sales of their respective handsets have been negligible.
And given that Microsoft's own Lumia sales have collapsed - falling by 73% year-over-year - that doesn't bode well for the future of the platform.
Curiously, after the Lumia 520 was dethroned last month by the Lumia 535 as the most widely used Windows handset, it's now returned to the top spot. AdDuplex speculates: "Last month was the first since [the] official Windows 10 upgrade became available for the 535 which resulted in higher owner activity in apps as well. Now, when the novelty has worn off, it's back to 'normal'."
In the US, things remain fairly similar compared with last month. The Lumia 640 is still the most used Windows phone there - but there's still no sign of the latest Windows 10 Mobile handsets in the top 10.
The Lumia 950 - the smaller of Microsoft's two Windows 10 Mobile flagships - is just outside the top 10 in Germany, the only market in which it's come close to reaching such heights. Germany has traditionally been a strong market for higher-end Windows phones; the Lumia 930 and 920 are still both in the top 10 there.
The much older Lumia 635 is still the most-used Windows phone in France, and by a considerable margin. The Lumia 640 has climbed up to the number two spot over the last few months, but the entire top 10 is now made up of low- and mid-range devices there.
You can check out a deeper overview of this month's AdDuplex report here, including a detailed breakdown of handset usage in Poland, Ukraine, India and Brazil. AdDuplex will publish its full monthly report tomorrow on its website.