Today Microsoft announced the release of its Windows Phone 7.8 SDK, which is good news for developers who want to test their apps with the revised OS. The primary purpose of this release is to let developers test their live tiles with Windows Phone 7.8.

The updated SDK includes two images, one that simulates devices running 512MB of RAM and another that simulates 256MB of RAM. The SDK includes no new API's over the Windows Phone 7.5 SDK, which is no surprise.

This further enforces the idea that Windows Phone 7.8 will mostly be a cosmetic update and not much new functionality will be seen. On a more exciting note, legacy support is still alive as Microsoft says that the new SDK won't alter existing Windows Phone 7.1 emulator images.