The .NET Core 1.1 release adds official support for Linux Mint 18 and openSUSE 42.1 when it comes to expanded distribution coverage. The .NET core has also been made faster through using Profile-Guided Optimizations (PGO). They are building the Linux binaries with LLVM Clang and for the .NET Core 1.2 release they expect to use Clang PGO on that front. There are also 1,380 new APIs added to this core release.
More details on .NET Core 1.1 via msdn.microsoft.com.