Recent changes quietly made to the Windows 8 hardware certification guidelines suggest that Microsoft could be gearing up to debut a new, smaller "Windows Reader" tablet designed to compete with more portable devices like Apple's iPad mini.

Microsoft recently relaxed its hardware certification rules to allow devices with screen resolutions of 1,024 by 768 pixels at a depth of 32 bits. But the Redmond, Wash., company also warned developers that it doesn't mean they are allowed to develop hardware with low-resolution displays.

"This doesn't imply we're encouraging partners to regularly use a lower screen resolution," Microsoft said. "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 statement was viewed as "cryptic" by Ed Bott of CNet who suggested the change could hint that Microsoft is setting the stage to allow devices with smaller form factors. The company has been rumored to be at work on a so-called "Windows Reader" for some time.

The new resolution allowed for Windows 8 devices happens to match the display of Apple's iPad mini, which also sports a 1,024-by-768-pixel 7.9-inch screen. And the iPad 2, which Apple also continues to sell, features the same resolution on a larger 9.7-inch display, giving it a lower pixel density.

Windows 8 devices that run at Microsoft's newly approved lower resolution will lose the operating system's "snap" feature, which allows two Windows Store applications to be viewed simultaneously side by side. Manufacturers are required by Microsoft to disclose this loss "to avoid potential customer disappointment."

While Microsoft looks to lower resolutions, some expect that Apple will boost the iPad mini to a Retina-caliber display with a second-generation model this year. However, others have suggested that doubling the iPad mini's resolution on its small 7.9-inch display may be too difficult a feat to accomplish this year.