How do I update from RT 8.1 Preview to RT 8.1 Final?

On all my 8.0 and RT 8.0 machines the 8.1 update was sitting right at the front of the store, but on my RT 8.1 Preview machine there's just nothing. Do I have to do anything special? I searched online and didn't come up with any help.

I tried wsreset.exe and it didn't help.