Standards take time, the ISO spec is typically 2-3 years behind the current product.
But cheer up, the ECMA team just updated the VM spec a couple of months ago and the committee is resuming work on new features.
We are all pretty psyched about the next steps for the ECMA standards.
As for Mono, we already have C# 5 and many of the new class library features. Having two independent implementations helps coming up with a better standard.
The current version of Mono4Android and MonoTouch do not support async/await yet, but that is on the roadmap (once Mono 2.12 [currently in beta] is released).
But cheer up, the ECMA team just updated the VM spec a couple of months ago and the committee is resuming work on new features.
We are all pretty psyched about the next steps for the ECMA standards.
As for Mono, we already have C# 5 and many of the new class library features. Having two independent implementations helps coming up with a better standard.