With the end of XP support only 7 weeks away Microsoft has extended Windows 7 sales. As for Windows 8, it has reached another milestone - 200 million licences have been sold.

Back in January 2013, two months after its launch, Windows 8 had sold 60 million licences,  taking into account both upgrades and sales to OEMs for new devices, and Microsoft claimed that this was a similar sales trajectory to that experienced with Windows 7.

Four months later, in early May Microsoft officials announced  the milestone of 100 million Windows 8 licenses sold and again claimed that this was on a par with the number of Windows 7 licenses sold in its first six months on the market.

Since then there have been no more blazoned announcements. Rather the news that more than 200 million Windows 8 licences have now been sold emerged during an appearance by Microsoft Marketing chief Tami Reller at the Goldman Sachs Technology & Internet Conference and was picked up by ZDNet's Mary Jo Foley who was listening to the webcast.

So Windows 8 has reached the 200 million mark after 15 months, and by 15 months Windows 7 was already at 300 million.

This chart produced by Emil Protalinski for TNW shows just how far the Window 8 trajectory lags compared to that of Windows 7, although, as Protalinski notes, we can't be sure where they started to diverge as there are only three data points for Windows 8.

(click in chart to enlarge)

There is also a pronounced upward flick at the end of the graph - which is perhaps counter-intuitive so far into the Windows 7 lifecycle.

Or is it?

In early December, Microsoft announced that it would end Windows 7 OEM sales at the end of October 2014. Soon afterwards, amid a flurry of media attention, Microsoft retracted saying that this was an error and the date was still to be determined. It's difficult to know if the prospect of no further OEM sales was the cause of the increased sales in the last couple of months but the current strength of these sales has presumably influenced Microsoft's latest decision.

Although it has reinstated the date of October 31, 2014 as the cut-off for consumer versions of Windows 7, i.e. Home Basic, Home Premium, and Ultimate, there is no firm date for the end of Windows 7 Professional OEM sales. It is however at least twelve months away as a note on the updated Windows lifecycle fact sheet  says that Microsoft will provide one year of notice prior to the end of sale date.

The fact that it is the extension is only for the corporate version of Windows is significant. For corporate customers migrating an operating system is a lengthy process and given that so many customers, both at home and in business are still clinging to Windows XP, which is now within 50 days of end of support, not providing an extension might deter upgrading with businesses perhaps deciding to stick with XP until Windows 9 becomes available.

As for Windows 7's support policy, the dates remain the same. The operating system will end mainstream support (which is to say, non-security bug fixes, extra features, and warranty claims) on January 13, 2015 and will be in extended support (security fixes and paid support) until January 10, 2020.