This is an exciting week for Windows Phone 7.5 developers. Yesterday, we started rolling out the update to customer handsets and shared lots of developer goodness and started rolling out RTM updates to dev devices; today, I’m pleased to announce that the Windows Phone SDK 7.1 RTW release is now available on the Microsoft Download Center for immediate download and update.

Windows Phone SDK 7.1

The existing SDK has allowed developer to create and publish apps optimized for Windows Phone 7.5 since August. The Release to Web (RTW) release consists of seven additional release languages, final finishing touches to the tooling experience, a handful of bug fixes, and additional upgrade logic to provide a better installation process for users coming from earlier tools. In total, the RTW release is available in the following nine languages:

With this release, we recommend/ask that Windows Phone developers do the following three things…

1. Download and install the WPSDK 7.1, updating either your WPDT 7.0 RTW or WPSDK 7.1 pre-release installations
2. For already submitted apps (7.0 or 7.5), it’s worth checking into your App Hub account and cross-submit your apps to make them are available in the new WP7.5 markets
3. If you haven’t submitted your Windows Phone 7.5 app yet, it’s a great time to get it going; folks are excited and updating their phones – let your app light up on Mango!
   (If you already built and submitted your Windows Phone 7.5 app using the RC tools, you don’t need to do anything – there is no need to recompile and/or resubmit – it’s all good )

 
The Windows Phone SDK 7.1 and the corresponding developer platform underlying Windows Phone 7.5 is the result of a ton of great feedback from developers over the past year. Of all these updates and changes, I would like to highlight my favorite five things that have resulted from your feedback:

1. With MIX11, we launched the WPDev Feedback site on the UserVoice platform as a place for developers to post suggestions and capability requests; yesterday, we reskinned the site to use the new Windows Phone chrome, and we will start providing more feedback on submitted suggestions starting next month. If you haven’t already, head over there and file your suggestions and feedback for future releases!
2. With the Beta 2, we provided developers with a program to get a pre-release ‘Mango’ update on their retail phones. This has enabled our developer base to build and test their apps in time for Windows Phone 7.5 consumer release (yesterday!).
3. The tools are more widely available: 4 additional languages supported in WPSDK 7.1, and now also available for install via the Web Platform Installer (WebPI) client and using WebPI's Contextual Installation
4. The tools now include some great new capabilities:
   • NuGet allows you to easily keep your plug-ins and code library packages up to date
   • The profiler just plain kicks – who doesn’t love being able to see where performance bottlenecks are occurring in their apps?
   • Time to market for apps has been significantly decreased and first pass rates increased with the inclusion of the Marketplace Test Kit
   • The emulator supports the ability to feed in location and accelerometer data, as well the ability to take screenshots
   • The Microsoft Advertising Ad Control is now included as part of the WPSDK installation (and now available in 11 countries outside the US)
5. The underlying developer platform includes a massive number of API changes and capabilities that developers have been asking for (background agents; fast app switching; Silverlight 4; XNA/Silverlight Interop; what is there not to love here?)

‘Mango’ - MIX11 to Now

This release represents the final step in a journey we started on in April at MIX11, with two betas (Beta 1, Beta 2, and the Refresh) and an RC release. Given that almost everything in the RTW tools has already been discussed here and on many other blogs, I’d like to take a few paragraphs to reflect a bit on the last six months since MIX11; what’s in the tools; and all the great input and feedback that has come from the Windows Phone developer community.

• Hundreds of thousands of pre-release WPSDK downloads over the last few months
• 70,000+ unique developer devices have been successfully updated to ‘Mango’ over the course of the last three months
• 50,000+ visitors to the JumpStart videos, serving up over 450,000+ hours of video
• 20,000+ UserVoice votes submitted against 550 suggestions so far since the UserVoice forum launched with MIX
• 4200+ user posts in the ‘Mango Update’ App Hub forum, with 285,000+ post views
• 50+ cups of Tully’s Coffee consumed while processing Connect invites
• 8 devices came back to Redmond to receive intensive care

All of that being said, I would like to extend a heart-felt thank you to everyone that participated in the ‘Mango’ OS Pre-Release, and to everyone that have evaluated the pre-release tools. Thank you for helping to test the update process, yielding a better experience for our customers; and thank you for getting your apps built and tested in time for our Windows Phone 7.5 roll-out. It’s been great having you on board for the road to Windows Phone 7.5!

Most of all – thank you for being a Windows Phone developer, and collectively supporting our platform.