Microsoft may be playing their Windows Phone 7 development cards close to their chest - the perpetual message at MWC 2010 this week was "wait until MIX 2010 and we'll tell you more" - but that hasn't stopped leaks from tipping the company's plans. According to an XDA-developers forum thread, leaked OS 7.0 Application Platform documents have confirmed some of the expectations and hints from the WP7 launch, including that it's an almost entirely different environment from what developers are used to from Windows Mobile 6.5.3 and earlier.
Like the Zune HD, WP7 uses XNA, along with both the .NET Compact Framework and Microsoft's own Silverlight Flash-alternative. Microsoft also intend to be a whole lot more controlling as to what they let through onto the smartphones: developers will have access to a limited selection of managed APIs, and have to apply to use the native APIs if they find that provision insufficient. Functionality like accessing the camera will be permitted from the managed APIs, however, so it's possible that developers will be able to recreate their titles without needing to go through that secondary assessment process.
Each app will run in an isolated sandbox, but independent software vendors (ISVs) will have lesser access to functionality than OEMs and mobile operators (MOs). It's a far cry from the relative free-for-all of previous versions, and starting to look a lot more like Apple's approach to the iPhone OS, frankly.