The death of Windows Phone has been announced several times already, but there won’t be any more postponements after today. Indeed, the just-released build 15254.603 is the final build for Windows 10 Mobile version 1709, which the latest version of the OS that Microsoft released in late 2017.
Microsoft previously announced that end of support for Windows 10 Mobile version 1709 would happen in December 2019, but the company quietly changed it to January 14, 2020, last month. Anyway, the company says that this latest patch brings the same fixes included in the build 16299.1625 for Windows 10 version 1709. The list of fixes (mostly related to Windows 10) can be found below
Security updates to the Microsoft Scripting Engine, Windows Input and Composition, Windows Media, Windows Virtualization, Windows Storage and Filesystems, and Windows Server.
Even though Windows 10 Mobile is now unsupported, handsets should continue to work as expected, and the Microsoft Store should also continue to function normally, for now at least. Still, it's time to move on to greener pastures, and thanks to Your Phone and the Microsoft Launcher Android currently enjoys more synergies with Windows 10 than Windows 10 Mobile never had.