Although Windows RT was officially released nearly a month ago on Microsoft's Surface and on a handful of PCs from its OEM partners, Microsoft has been quiet about its support policy for RT.

Now, the mystery is partly resolved. In an update to its support lifecycle page, Microsoft has officially declared that it will support its initial Surface release for four years. That is, not coincidentally, long enough for a determined undergraduate to get through a conventional university degree program.

Normally, Microsoft supports consumer and business versions of Windows for five years (the so-called mainstream support phase) with business versions getting an additional five years of extended support.

Because Surface with Windows RT is a hardware-software combo, it plays by a different set of rules. Microsoft has decreed that its Mainstream Support End Date will be April 11, 2017, which is nearly 4-1/2 years after the product's initial release date. Because this device is considered a consumer device, there's no Extended Support End Date.

Update: On a separate page (see the Support Lifecycle Policy heading), Microsoft has updated its policy to provide additional support details for consumer hardware.

Microsoft's current policies offer "a minimum of ... four years Mainstream Support for Consumer Hardware products."

During the Mainstream Support phase, "Hardware repairs or replacements and parts are available throughout the support lifecycle. Services are free for products under warranty and available for a fee for products out of warranty. ... Updates are available for the software/firmware and OS that is embedded into the hardware (except for Surface devices, which is covered by the support lifecycle policy for the Operating System on the device)."

Additional details are available in this FAQ, which notes: "For Surface devices, any Surface software installed, embedded or downloaded on the device is subject to the software lifecycle support policy for that software (unlike other HW devices such as Xbox). ... The hardware support lifecycle policy applies only to the Surface hardware (and as stated above not the Surface software). For Surface devices, that policy affects only the tablet device and hardware based accessories (and for example not to soft goods accessories such as cases)."

That means that anyone who buys a Surface with Windows RT can expect firmware updates until at least April 2017. Support for Windows RT and for the included Office Home and Student 2013 software should be available for the minimum five-year period defined for consumer software. And there's ample precedent for Microsoft to extend that end date.

That support schedule, while a trifle skimpy by Redmond's normal standards, is downright generous compared to tablet rivals. Apple's original iPad, released in early 2010, no longer qualifies for iOS updates, security or otherwise, and it's barely 2-1/2 years old. Similarly, anyone who buys a Google Nexus 10 has no idea how long it will receive updates. The same is true for tablets from Google's many Android partners, including Samsung. Given Google's track record with orphaned Android devices, it's hard to believe these devices will be supported for more than a couple years.

Likewise, both Amazon's Kindle and Barnes & Noble's Nook are in uncharted territory in terms of support.

Surface isn't the only Windows RT device, of course. A handful of OEM partners, including Dell, Acer, and Samsung, are (or soon will be) shipping devices with Windows RT. So far, Microsoft’s support lifecycle page is mum on their expected support dates. Presumably, Windows RT, as a consumer operating system, will be supported for five years per the current policy. But as of today, the official Windows RT Product Support Lifecycle Policy FAQ doesn't list any support lifecycle dates. Instead, it simply says:

Microsoft will make software updates, including security updates, available for Windows RT. Additional information regarding the Windows RT lifecycle policy will be communicated as available. … Office Home and Student 2013 RT has the same lifecycle policy as Windows RT.

Hat tip to an anonymous reader.