As announced earlier today on the Windows Phone Developer Blog, the Windows Phone SDK update for Windows Phone 7.8 has been released. The Windows Phone SDK update for Windows Phone 7.8 is a patch and not a standalone product, so you must install the Windows Phone SDK 7.1 or the Windows Phone SDK 8.0 before you can install this update. Here is some information to help you get started installing and using the Windows Phone SDK update for Windows Phone 7.8:

What’s new in the Window Phone SDK update for Windows Phone 7.8:

• Windows Phone 7.8 emulator image.
• Windows Phone 7.8 256MB emulator image.
• Bundled install of the features included in the Windows Phone SDK 7.1.1 Update if you have the Windows Phone SDK 7.1 installed.

Download and getting started links for the Windows Phone SDK update for Windows Phone 7.8:

• Windows Phone SDK update for Windows Phone 7.8 download page
• MSDN topic: Adding Windows Phone 8 and 7.8 Tile functionality to Windows Phone OS 7.1 apps
• Blog post: Windows Phone 7.8 and Windows Phone 8 Live Tile light up for Windows Phone OS 7.1 apps