Though much of Microsoft's technical strategy for Windows Phone 7 materialized at MIX last month, the company stayed hazy on a handful of key details -- portions of the hardware specifications were left to guesses and hearsay, for instance, as was the software update strategy. Much of that appears to be coming to light now thanks to a leaked "architecture guide" slide deck where we seeing that retail devices will be required to feature cameras (that could be a problem for corporate devices in high-security environments), FM radio tuners, compasses, and proximity sensors, among other more obvious features like capacitive touchscreen displays; of course, these are requirements for the initial volley of launch devices at the end of 2010, and it's probably reasonable to assume that future chassis specs will be tweaked.

Moving to software, the deck confirms that a Windows Live ID will be required to set up the handset -- much the same way that Android strongly encourages the use of a Google account -- and that application purchases will be tied to the ID. The update mechanism, which has all but failed Microsoft in Windows Mobile thus far, looks to be very well controlled this time around -- like Kin, small updates will over the air, while larger updates will require tethering and management through the Zune software on your PC. Microsoft will manage the process -- not the manufacturer or carrier -- though device- or carrier-specific customizations can be pushed through the same mechanism. Speaking of OEM customizations, the deck emphasizes just how tightly Redmond will be controlling them: IE's default search engine can be changed, but everything else on the phone will still go through Bing, for example. OEMs can add no more than six (or 60MB) worth of custom apps, and while custom home screen tiles can be added, none of the standard Microsoft ones can be changed or removed. It's pretty draconian, yes -- but considering how desperately these guys are in need of a fresh, starkly different mobile strategy, it's probably a good thing.