Microsoft typically provides five years of mainstream support for any Windows version, but the firm revealed this past week that its recently released Surface with Windows RT tablet will be supported for about four and a half years. That said, Windows RT, the OS that runs on this first Surface device, will presumably be supported for the full five years.

This news has triggered a wave of complaints and support, both from the expected circles. But it’s important for Surface users to understand that this device will most likely surpass the support lifecycle of its closest competitor, the Apple iPad. For example, the original iPad, which was released in early 2010, isn’t eligible for upgrading to iOS 6, the latest version of Apple’s mobile OS.

A search for Windows RT on the Microsoft product lifecycle site reveals the new schedule. Surface with Windows RT—the device—is supported until April 11, 2017, about four and a half years after its October 30, 2012, release.  Windows RT, oddly, doesn’t get a support end date, yet, and a linked Q&A does nothing to solve that mystery. But Microsoft’s Windows versions typically get five years of mainstream support, with business versions adding another five years of extended support. Windows RT is a consumer release, not a business release.

The obvious question, of course, is what “support” means. ZDNet’s Ed Bott believes that “anyone who buys a Surface with Windows RT can expect firmware updates until at least April 2017.” But I take “support” to mean what it has meant traditionally: Windows Update-based software updates only, especially toward the end of that life cycle.

Looking ahead, a bigger question emerges. Will Surface and other Windows RT devices be eligible for upgrading to Windows RT 2.0 or whatever the next major release is called? My guess—and it’s only a guess—is no, and that Microsoft will treat those devices as the standalone appliances they are. If this is true, it makes the support lifecycle all the more important. But again, compared with iPad, or the strange world of Android (where no upgrade is a given), Surface still comes out ahead.

Read more about Surface in "Microsoft: Surface Sales Far From Modest" and "Taking Surface to Work."