Current Version Plugin Windows Presentation Foundation

Windows Presentation Foundation or WPF plugin was installed on many Windows computer as part of a Windows update by Microsoft. Mozilla blocked this plugin and disabled because plugin had a major security vulnerability that can be exploited by malicious websites update.
Block was removed two days later and this plugin does not run by default in Windows 7. Reinstallation of .NET Framework 3.5 SP1 is required to install this plugin and add support for XBAP applications. There is another way of enabling support for XBAP application by copying files from a working windows XP or Vista to Firefox plugin directory. Depending on the framework version, you can find these DLLs in these directories.

c:\Windows\Microsoft.NET\Framework\v3.5\WPF\NPWPF.dll – for v3.5 [SP1]
c:\Windows\Microsoft.NET\Framework\WPF\NPWPF.dll – for v4

This plugin was used to view certain multimedia content on websites. Microsoft .NET Framework 3.5 SP1 installed this plugin in Firefox browser. Windows Presentation Foundation is developed by Microsoft for building rich Windows smart client user experiences that incorporate UI, media, and documents.
The security vulnerability is now fixed and you can download MS09-054 patch to enable this plugin.
Windows Presentation Foundation is next-gen system for creating windows applications with advance user experiences. Both standalone and browser-hosted application can be creating using WPF.
WPF was previously knows as Avalon and it was released as part of .NET Framework 3.0. It is also utilized in Microsoft Silverlight to provide embedded web controls. Till now Mircosoft has released 4 major versions of Windows Presentation Foundation, WPF 3.0 (Nov 2006), WPF 3.5 (Nov 2007), WPF 3.5sp1 (Aug 2008), and WPF 4 (April 2010).