As we close down on the release, we're actually pushing out an update to the Silverlight RC build in the next couple of hours. The update is Sunday night's drop - build 20730 (the last release was 20724), and I'm going to informally dub it "RC2" for ease of reference.
This is one of a few critical updates that we'll be pushing down over the next couple of weeks to test the update mechanism. If you've set your update options to prompt on install, you'll see a dialog very like the following when you next visit a page that contains Silverlight functionality:
All updates will require a restart at some time to take advantage of the functionality changes. All prompted updates can be “postponed” by not restarting the process until you are ready; when you next restart the browser or open a new window, you'll see the updated version (you can right click on any Silverlight content and choose "Silverlight Configuration" to see which build is actually running).
There's no additional work required to support this release - there are zero breaking changes compared to the RC1 release, and you don't need to update your silverlight.js file or anything else for your code to work.
To be clear, we're not pushing this update out because we've found a security issue; it's more of a public test of our update broadcast system (with the added bonus that you get the latest bits installed). We'll do a few more of these on an approximately weekly basis until we release the final Silverlight 1.0 bits; from that point on we'll only update like this as necessary to fix a critical issue.