At Microsoft's shareholders' meeting today, Steve Ballmer said Windows Phone 8 sales were off to a "great start." The combination of new software and more powerful hardware had resulted in four times as many sales as this time last year, the Microsoft CEO said.

The two high-end devices, the Nokia Lumia 920 and the HTC Windows Phone 8X, have both been selling out in a number of markets.

How many units that actually translates into is left conveniently unspoken. Shanghai Securities News reports that Nokia has already taken orders for 2.5 million Lumia 920s in the 20 days the phone has been on the market. This isn't far off the 2.76 million Windows Phone handsets that Gartner estimates were sold in the fourth quarter of 2011. The Lumia 920 is on track to sell more devices this quarter than all Windows Phone OEMs managed a year ago.

Microsoft also talked about Windows Phone 7.8 for the first time since June. Windows Phone 7 devices won't be upgradable to Windows Phone 8. Instead, they'll receive a small update branded Windows Phone 7.8. Previously, Microsoft confirmed this update would include the new Start screen with its variable Live Tile sizes. The company now says it will include a little more than that, though not much more: 7.8 will carry more colors, the option to use Bing images on the lock screen, and protection against having your phone wiped due to too many failed PIN attempts.

The update will be delivered to "as many devices as possible" in early 2013. This language implies that not all devices from all carriers are likely to receive the update. If true, this continues the haphazard update support plaguing the platform.

Windows Phone 7.8 won't be limited to existing devices, though. New models are due to debut in emerging markets that will run this new version of Microsoft's old smartphone operating system. Though these won't run apps designed for Windows Phone 8, both the old operating system and the new one will run apps built for Windows Phone 7.5.