CEO Satya Nadella has been personally testing "significant updates to Windows", for several months
Microsoft will stop support for Windows 10 on 14th October 2025.
The company 'announced' the news in an updated Windows lifecycle document, stating that support for Windows 10 Home, Pro, Pro Education and Pro for Workstations would end in four years' time.
It means the company will cease to provide Windows 10 technical support for any issues, software updates or fixes after that date.
This is the first time that Microsoft has described the end of support for Windows 10, after famously saying it would be "the last version of Windows" back in 2015.
Thurrott, which broke the news, said the updated support page earlier detailed end of support dates for only specific Windows 10 versions, not the entire OS.
Microsoft has since confirmed its plans officially, stating it 'will continue to support at least one Windows 10 Semi-Annual Channel until October 14, 2025.'
Microsoft introduced Windows 10 about six years ago, on 29th July 2015, with a free upgrade offer for users of Windows Vista and Windows 7 - thought to be largely responsible for the fast uptake of Windows 10 compared to the lagging Windows 8.
"We think of Windows as a service... and just like any internet service, the idea of asking 'What version are you on?' will cease to make sense," Terry Myerson, Windows boss at the time, said in January 2015.
Windows 10 is the source of 14 per cent of Microsoft's total revenue, receiving two updates each year since its launch.
Announcing the end of support for Windows 10 is another hint from Microsoft that it is now fully ready to launch a new version of Windows - although whether it will just drop the Windows 10 brand, or require a new purchase, is still unclear.
Although the company never mentioned maintaining the Windows 10 brand in perpetuity, it did promise to keep Windows current once licensed to a device at no cost.
There have been several reports that Microsoft is looking at a major Windows shake-up this year.
Earlier this month, the company announced a special Windows event on 24th June to unveil 'the next generation of Windows'.
The announcement came about a week after CEO Satya Nadella teased major enhancements to Microsoft's OS at Build 2021, promising the next version would offer more opportunities for creators and developers.
Nadella said he had been personally testing "the most significant updates to Windows" for several months, and was "incredibly excited" about it.
Microsoft has not yet officially said what the next generation of its OS would be called, although they have been hinting at Windows 11.
Microsoft was said to be working on a new Windows update (codenamed Sun Valley) in January, which would involve a major UI overhaul 'signalling that Windows is BACK'.
Reports also claimed that Microsoft was also working on a Windows Store revamp, which would offer more flexibility to developers when distributing their software.