Microsoft has quietly changed its OEM certification guidelines for Windows 8 to allow devices with lower screen resolutions, a move that could mean smaller Windows tablets are on the way.

ZDNet's Ed Bott was first to spot the rule change made earlier this month, which lowers the minimum screen size for a device bearing the Windows 8 logo to a petite 1024-by-768 pixels.

It was also the resolution used by many of the first wave of Windows 8 fondleslabs, such as the Samsung Slate, the Asus Vivo, the Lenovo ThinkPad Tablet, as well as Microsoft's own Surface RT.

The problem? As El Reg reported in January, sales of such tablets – all of which have screens measuring 10 inches or larger – weren't particularly strong over the 2012 holiday shopping season.

Meanwhile, customers were snapping up devices with smaller screens, such as the Asus-built Google Nexus 7, Amazon's Kindle line, and the iPad mini – and some analysts have predicted that the iPad mini will outsell its larger cousin this year.

So big tablets are out, smaller ones are in. What's Microsoft to do?

As it happens, the new Windows 8 minimum of 1024-by-768 is the exact screen resolution of the current-generation iPad mini. See where Redmond is going with this?

The Nexus 7's screen is actually a little larger at 1280-by-800, but even that wasn't roomy enough under Microsoft's old certification rules. Under the new guidelines, we could see devices with the Nexus 7's form factor bearing the Windows 8 logo.

We could even see other things, too. Microsoft says the new screen-resolution guideline applies "across all Windows 8 system form factors" – so there may yet be a Windows 8 netbook in your future, if that's the sort of thing you're into.

There is a catch, though. When the screen resolution is lower than 1366-by-768, Windows 8 disables "snap," the feature that allows users to run two Windows Store apps side-by-side at the same time.

Thus, as part of the new Windows 8 certification guidelines, manufacturers of devices with lower screen resolutions must file a form with Microsoft explaining how they will "provide appropriate, clear, and conspicuous disclaimers" to let customers know that snap isn't available.

What's more, even though Microsoft is relaxing its certification guidelines, it doesn't really sound all that bullish on the idea. As the revised guidelines explain:

This doesn't imply that we're encouraging partners to regularly use a lower screen resolution. In fact, we see customers embracing the higher resolution screens that make a great Windows experience. We understand that partners exploring designs for certain markets could find greater design flexibility helpful.

That "certain markets" part at the end could be the kicker. Microsoft could be referring to OEMs that build devices for specific vertical markets, such as health care, finance, or oil and gas.

More likely, however, it's talking about those markets where a $700 Windows tablet simply won't fly. We've already seen low-end Android tablets selling in Asia for as little as $30. Microsoft's relaxed hardware requirements could merely be a concession to allow OEMs to build Windows kit that's more price-competitive.

But if that is the plan, don't expect such devices to retail in the US or Europe anytime soon. Given Microsoft's focus on affluent consumers with its Windows 8 and Surface ad campaigns, expect the low-end devices to ship to developing markets only, while mainstream kit continues to look more or less like it does now. ®