The first version of WPF was released as part of .NET Framework 3.0 in November 2006. On 11/16/2007, we released the second version of WPF, as part of .NET Framework 3.5 (code-named Orcas). We call this WPF 3.5.
WPF 3.5 has a number of exciting new features and a number of product fixes and improvements, quite a few of them reported and suggested by our customers.
For a full list of the new features in .NET Framework 3.5, check out this article on MSDN and this article on WindowsClient.net. Below is a summary of changes and additions in WPF 3.5. Some of the items below are large features, others are small incremental changes.