Last year, Microsoft's Bob Muglia said the firm's Silverlight strategy had "shifted", calling HTML5 the only "the only true cross-platform solution for everything".
Earlier this year, it banned plugins from Internet Explorer on Windows 8 in the Metro UI, effectively dropping Silverlight from that part of the next-gen OS.
Silverlight 5 comes a full year after the beta, bringing with it improved graphics and a performance boost, Microsoft said.
"New features in Silverlight 5 include Hardware Decode of H.264 media, which provides a significant performance improvement with decoding of unprotected content using the GPU," the company said in a blog post, adding it also includes "Postscript Vector Printing to improve output quality and file size, and an improved graphics stack with 3D support that uses the XNA API on the Windows platform to gain low-level access to the GPU for drawing vertex shaders and low-level 3D primitives".
Silverlight 5 will also extend Microsoft's "Trusted Application" sandboxing model, meaning "users won’t need to leave the browser to perform complex tasks".
The free download is available here.