As you might know, Windows Phone 8 offers a greatly updated start screen over it’s predecessor, Windows Phone 7. Users of Windows Phone 7 will get updates to version 7.8 in the first quarter of 2013, but developers can start building for this version right now using the Windows Phone 7.8 SDK update. The update is available on MSDN here: http://dev.windowsphone.com/en-us/downloadsdk
Note that you have to have either the 8.0 SDK installed (here’s my experience with doing it: http://blogs.msdn.com/b/lmoroney/archive/2013/01/23/getting-started-with-windows-phone-8-development.aspx ), or the 7.x SDK installed already.
Once it’s downloaded and installed, create a quick app (File->New Project, Select ‘Windows Phone Application’ under C#), and you’ll be asked if you want to run it on Windows Phone 8 or Windows Phone 7.1.
Make sure that you select Windows Phone OS 7.1. Yes, I know you’re thinking of building 7.8, but there’s a little bit of a nuance here. This SDK update gives you 7.8 emulation images that you can use to test the main new feature in 7.8 that differs from 7.x – and that is the different tile sizes that are reminiscent of those found in Windows Phone 8.
Once you’ve done this, take a look at the ‘Emulation’ section in the toolbar at the top of Visual Studio Express. Drop it down, and you’ll see the new options for 7.8.
When you run your application, the emulator will now run with 7.8 style tiles.
You can emulate the user action to resize the tile by holding the mouse button down over the tile for a few seconds:
And this will allow you to change the tile size:
You’re now ready to use the tools to bring your WP7 app tiles up to date with Windows 7.8. You can see how to do that here: http://blogs.msdn.com/b/lmoroney/archive/2013/01/28/create-a-windows-phone-7-flip-tile-and-update-it-to-windows-phone-8-style-using-the-windows-phone-7-8-sdk.aspx