Submitting different XAP files for WP7 and WP8

If you are a Windows Phone developer, chances are you already know that your Windows Phone 7 applications are working on Windows Phone 8 without any changes. However, WP8 introduced new screen resolutions and applications that are not made for them may look a bit stretched. What’s more, as the platform continues to grow, future versions are likely to stop supporting WP7 apps.

Luckily, Microsoft has provided developers with a simple way to upgrade their apps and keep a two versions on the store, one for each OS version. In this post, I’ll go through the process very quickly to clarify some points that you may come across. It’s supposed to be a simple guide but leave a comment if you’d like to know more or if you encounter any problems.

Upgrading your application

This one is a piece of cake. First things first, you should make a copy of your project as, once you upgrade, you can’t go back to the old version. Then, just fire up Visual Studio, right-click your project in the Solution Explorer and select “Upgrade to Windows Phone 8.0”.

For most applications, that’s about it and everything will work just fine. However, if you’re using an unusual API or library you might run into compatibility problems, so make sure you test the app thoroughly before submitting.

Visual Studio 2013: Upgrade to WP8

Submitting the upgraded version

Now that we’ve got the XAP file, it’s time to have a look at the Dev Center process. It’s fairly straightforward so I’ll just outline the steps but first a small checklist of the things you got to have prepared for your submission.

WP DevCenter: Add new xap

Now that you’ve got all you need, it’s time to submit that XAP! I’ll go through the process in some simple steps that shouldn’t be hard to follow:

  1. Once you’re on the Dev Center and have selected your application, create a new update using the link at the top of the page. This will create a new update instance preloaded with information from your last submission.
  2. Go into the second section “Upload and describe your XAP”
  3. The trick here is to locate the “Add new” link just below the XAP information table as it’s not standing out too much.
  4. Upon clicking it, you’ll be asked to upload your XAP file and the system will create a new entry ready to be filled out.
  5. After going through the admittedly tedious task of uploading screenshots, writing a description etc just click the “Review and submit” button and you’re set to go.

That’s all, everything should be working fine by now and you should be receiving a certification e-mail shortly. The Dev Center is built in such a way that makes it easy for you but feel free to share any concerns in the comments section!

Important Note: As Martin Suchan pointed out in the comments, “make sure the version number of your WP8 package is higher than the version number in WP7.1 package, WP8 users might get the new WP7.1 version instead.” There are reports that the issue is fixed (thanks Jeremy Sinclair!) but either way it would be a good idea to keep this in mind.

If you’re looking for more details around upgrading an application to Windows Phone 8, there’s a great MSDN article: Upgrading Windows Phone 7.1 Apps to Windows Phone 8

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