Custom dll in Silverlight app not getting updated on one client

I'll admit up front my experience with Silverlight is minimal.

I'm working on a SL app that also supports shipping custom screens in the form of a custom DLL. I made a change to said DLL and it's gone through build and deployment to a QA box for internal testing. When one points IE to the ap开发者_如何学Cp, for three of us the updated version of the custom screen is coming up, but for a fourth person the older version of the DLL is somehow being referenced.

We've done some usual suspects (closed sessions, cleared his browser's cache, even installed Firefox) but he's still referencing the older version of the DLL. We have verified that the DLL on the server we're all hitting is the newer version (but that's no surprise since the rest of us are getting it).

There seems to be something specific to the client machine (or maybe that guy himself is just unlucky). Where would you look next?

First step is to install fiddler on the "fourth" persons machine. Examine the request to server for the new dll.