A recent build of Microsoft’s upcoming Windows Phone 8 Software Developer Kit (SDK) leaked online a few hours ago, revealing a number of unannounced features for consumers and developers alike. The SDK is located on a Chinese website and requires a third-party download manager, but it appears to be legit.

One of the coolest features is the ability for apps to place notifications on the lock screen, just like on Windows 8. Developers will be able to change the app icon, count, and text. So if you’d prefer to have the full text of recent tweets rather than your next calendar appointment, you can do that. Or maybe you just want to know the number of unread items in your RSS feeds. You can do that too. Apps will also be able to change the lock screen wallpaper, paving the way for “image of the day” apps, lock screen artist wallpaper like the Music + Video Hub already has, and much more.

Microsoft is also adding a wide variety of new features to the Map app, such as 3D transparent landmarks, light/dark mode, and 0° or 45° pitch. The road and aerial views will also be joined by two new ones: hybrid and terrain. You’ll be able to download maps for offline access too.

Windows Phone 8′s app experience has been improved as well. Photo apps now have the ability to auto-upload pictures in the background, much like SkyDrive and the WP7 Camera app. Of course, these apps will always require your permission first. App-to-app and app-to-device communication is now supported via Bluetooth, and you’ll be able to set file associations for the app auto-launcher. The file associations menu will suggest compatible apps if none are installed on your device, and it’ll let you choose which app to launch if there’s more than one available.

As you might expect, the SDK also includes the features announced at the Windows Phone Summit last month, such as the redesigned Start screen, Data Sense app (formerly known as Data Smart), improved Camera functionality, Xbox Music branding in the Music + Video Hub, Microsoft Wallet, app voice commands, and a wide variety of enhancements for developers.

As always, keep an eye on Anythingbutiphone’s great Windows Phone 8 feature list for the latest on all of the new, confirmed, rumored, and debunked features.

[WPXAP via WPCentral | SuperSite for Windows]