- Rx.NET
Added XNA 4.0 Xbox 360 support.
Added Windows Phone 7 support.
Fixed xna crash in CurrentThreadScheduler.
Removed conflict of EnumerableEx.Zip and Enumerable.Zip on Silverlight 4.
Fixed ForkJoin bug on empty source.
Added drain operator.
Added Rx extension methods to BCL via System.Reactive.ClientProfile and System.Reactive.ExtendedProfile assemblies.
Fixed bug to ensure subjects clear observers once OnCompleted fires.
Added support for the new C# await keyword (Observable.GetAwaiter).
Added ToTask and ToTaskLast operators
Added IAsyncEnumerable interface and all standard query operators for this interface.
Fixed bug in Observable.Concat, Observable.Catch and Observable.Merge to dispose of source enumerable correctly.
Added NuPack support (packages will be online soon)

— rx.js
Changed default schedulers to immediate where possible to match rx.net semantics.