Microsoft is generally tight-lipped about its operating system releases, but its efforts to stay mum on the topic were apparently undermined by one of its own last week.

In an Oct. 22 blog post from Microsoft Netherlands, the writer noted: "Furthermore, Microsoft is on course for the next version of Windows. But it will take about two years before 'Windows 8' is on the market."

Apparently, the lines were written as an afterthought to a commemorative entry about Windows 7's first anniversary, but was picked up, translated, and posted yesterday by winrumors.com. CNet also posted a screen grab from the blog.

This would mean at least three years between versions since Microsoft launched Windows 7 in October 2009, roughly two and a half years after its predecessor, Vista.

As CNet noted, all Windows 8 references have been removed from the entry since winrumors.com picked it up yesterday. It now discusses the first service pack to Windows 7 as well as Windows Live Essentials.

This isn't the first Windows 8 slip. In June, a blogger posted what he claimed was a Microsoft presentation on Windows 8, which included a slide titled "How Apple Does It."