Several of my customer and partner contacts have told me they have
heard from their own Microsoft sources over the past couple of
weeks that Silverlight 5 is the last version of Silverlight that
Microsoft will release. They said they are unsure whether there
will be any service packs for it, and they are also not clear on
how long Silverlight 5 will be supported by Microsoft.
I have never installed Silverlight on a single computer I own.