Microsoft deferred pretty much all technical questions at MWC 2010 about Windows Phone 7 to their upcoming MIX conference, but they've apparently relented and released a little information ahead of time. Key is that they're using Silverlight and XNA for development, along with .NET, Silverlight being Microsoft's Flash alternative (and making its first appearance on a Microsoft mobile platform with WP7) while XNA is found powering 2D and 3D gaming on the Zune HD.
The news comes courtesy of Charlie Kindel, on Microsoft's Windows Phone developer experience team, who in the process confirms that applications written for Windows Mobile 6.5.3 and earlier versions won't be compatible with the new platform. Kindel says that Microsoft will be supporting these devices "for many years to come", though it's obvious that the company expects devs to jump on board with Windows Phone 7.
"The expertise and familiarity with our tools is not lost. If you are a .NET developer today your skills and much of your code will move forward. If you are Silverlight or XNA developer today you’re gonna be really happy. New developers to the platform will find a cohesive, well designed API set with super productive tools." Charlie Kindel, Microsoft
Apparently Microsoft have been meeting with hundreds of developers and ISVs over the past year to find out exactly what they want from a platform, and almost 70-percent prioritised "ease of use". Of course, we'd also guess that they look at the potential for success that a platform faces - contrast, say, iPhone OS development versus Palm's webOS as it stands currently - but Microsoft seem like a pretty reasonable bet there, too. More at MIX 2010, we're told.