There has been a major refactoring on how the XLabs project is structured so your existing project based on the 1.2.x will break. The reason for the refactoring was simple; separate functionality that does not depend on Xamarin.Forms into different assemblies. This allows the use of functionality like IoC, Serialization and even platform specific services without referencing XF.
To upgrade:
1) Uninstall any existing Xamarin.Forms.Labs packages from your project.
2) Optional but recommended: update to XF 1.3.2.6316.
3) Install XLabs.Forms package to your projects (PCL, iOS, Droid & WP).
4) Refactor code to reference the correct namespaces.
Due to separation from XF dependency the services from XLabs.Platform are not registered with DependencyService class. The preferred method would be to use the Resolver class instead but to not break existing code (more) there is an option to register the services with the IXFormsApp initialization (enabled by default):
https://github.com/XLabs/Xamarin-Forms-Labs/commit/971655d5135740638981cd6adf62ca193324731c
@TheRealJasonSmith any chance to make this thread a sticky for a while? There have been many threads about the unified releases and Labs 1.2.x issues as the old NuGet packages do not support unified iOS.