1.0

Dates: 5 Sep 2007 – 14 Oct 2008

Framework: DOM (JavaScript)

Notable features:

 

2.0

Dates: 14 Oct 2008 - 9 Jul 2009

Framework: .Net 3.5

Notable features:

 

3.0

9 Jul 2009 – 15 Apr 1010

Framework: .Net 3.5

Notable features:

4.0

Date: 15 Apr 2010 – present (current release version)

Framework: .Net 4.0

Notable features: WCF RIA Services; web cam support;

 

5.0

Currently in beta. Due at the end of 2011?

Framework: .Net 4.0 ??

Notable features: GPU rendering of video and 3D graphics; 2 threads (one for program execution, one for rendering);

 

6

[there was some info on arsTechnica]

Framework: .Net 4.5 ??

Notable features: closer integration with the Windows operating system. Windows 8 is expected to use Silverlight 6 for native applications.