Our may have shown it to be a half-hearted update at best, but a substantial portion of Microsoft’s base of installed phones won’t even have a chance to experience it.

A report by AdDuplex, an ad network running on top of Windows devices, found that four of the top 10 Windows phones won’t be allowed to upgrade to Microsoft’s latest feature update. That works out to about 40 percent of all Windows phones already in the hands of users.

AdDuplex

Only 6 out of the top 10 best-selling phones are eligible for the Windows 10 Mobile Creators Update, AdDuplex found.

Just 13 phones are eligible for the Windows 10 Mobile Creators Update: some recent Lumias (the 550, 640/640XL, 650, and 950/950XL), two Alcatel phones (the IDOL 4S and OneTouch Fierce XL), the , and a few others.

Unfortunately for Microsoft users, that means many popular older phones can’t be upgraded. The Lumia 535, the third-most popular Windows phone, is ineligible, as well as the eighth, ninth, and tenth most popular phones: the Lumia 930, the Lumia 730, and the Lumia 540. The recent , as well as popular older phones like the Lumia 1520 are similarly excluded. By AdDuplex’s standards, 39.2 percent of all Windows phones won’t be eligible to receive the Creators Update. 

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