Microsoft acknowledged back in 2017 that it would no longer be developing Windows Phone. It's now announced it will completely cease support for the failed mobile OS at the end of 2019. 

That's important as security updates have continued to be made available. So many businesses and some consumers have continued with the mobile devices they bought several years back.

Ironically many of those companies and users bought Windows Phones because of the compatibility with Windows and the ease of deploying hundreds or thousands of units. 

According to a Microsoft support page, "Windows 10 Mobile, version 1709 (released October 2017) is the last release of Windows 10 Mobile and Microsoft will end support on December 10, 2019.

The end of support date applies to all Windows 10 Mobile products, including Windows 10 Mobile and Windows 10 Mobile Enterprise."

Microsoft's biggest missed opportunity

Let's not mince words - Microsoft completely stuffed up Windows Phone, or Windows 10 Mobile as it was later known.

At one point it was a promising new mobile ecosystem.

The forerunning Windows Mobile software was poor and lagged way behind the emerging iOS and Android for around three years after the iPhone launched in 2007.

But Microsoft surprised everybody at Mobile World Congress in 2010 with a genuinely innovative and usable mobile OS in Windows Phone 7.

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There was only one problem; the world's best software company failed to improve on the software, didn't attract enough developers or partners who understandably preferred Android's approach and Windows Phone never gained enough traction. Even its own Skype app took two years to arrive

Even more disastrously, Microsoft then bought Nokia's mobile division only to end up writing it off for $7.6 billion. 

Users of the Windows 7 laptop and desktop OS will also find support cut off this time next year - 14 January 2020 to be precise. Only enterprise will be supported after that, meaning there are a lot of businesses that will need to upgrade this year.