As we've known for a few months, the Windows client team at Microsoft is working on its first "feature-pack" update for Windows 8, supposedly due this summer/fall, which is codenamed "Blue."

But it turns out Blue isn't a Windows thing only, according to one very accurate tipster of mine who doesn't want to be identified.

Blue also is the way Microsoft is referring to the next substantial platform update for Windows Phone, the Windows Services (like SkyDrive, Hotmail, etc.), and Windows Server, according to my source. In other words, Blue is a wave of product refreshes which are not expected to arrive exactly all on the same day, but which are meant to be released more or less around the same time.

Before these various Blues come to market, there will continue to be minor fixes, firmware updates and new features added to Windows 8, Windows RT, Windows Services and Windows Phone. On the phone side of the house, for example, the first minor update, codenamed Portico , already has made its way out to a number of Windows Phone users.

Blue represents a major change in how Microsoft builds, deploys and markets software and services. To date, many Microsoft teams like Windows, Windows Live and Windows Server have been focused on delivering major platform updates every two to three years. The challenge is to get them to pivot around yearly platform updates, the first of which will hit as part of the Blue wave.

On the Windows side, the changes required to make this happen will be especially far reaching and pronounced. Instead of RTMing a new version of Windows once every three or so years, and then hoping/praying OEMs can get the final bits tested and preloaded on new hardware a few months later, Microsoft is going to try to push Blue out to users far more quickly, possibly via the Windows Store, my contact said.

There's still no word on specific new features coming to any of the Blue wave of products and services. But tweaks to the user experience, new dev-platform related bits, as well as new versions of Internet Explorer, Mail, Calendar, Bing and other integrated apps are likely to figure into the Blue picture, my source said. Blue will include some kernel and driver-level updates which could help with battery life and overall performance, according to my source, but backward compatibility with Windows 8 and Windows Phone 8 seem to be a priority.

I know there are still some Blue doubters out there, but Charon at Ma-Config.com found a recent mention of Blue in a member of the Windows team's LinkedIn profile:

Windows 9 is still seemingly on the roadmap, too, by the way, but it's not clear when Microsoft intends to deliver it. Charon also found a LinkedIn poster mentioning his work on Windows 9 recently:

For the time being, as executives like Windows Chief Financial Officer Tami Reller have said repeatedly, Microsoft envisions Windows 8 as something more than a one-season wonder. (Reller has said Microsoft considers Windows 8 a product "of multiple selling seasons.") That makes more sense if you think about Blue -- and Lilac and Fuchsia or whatever Blue's successors are codenamed -- as updates to Windows 8, rather than as Windows 9, 10, and beyond.

I very, very seldom post a single-sourced rumor. But go ahead and Tracour this Blue update. I'm feeling pretty solid on this one.