Installation Windows Phone 8.1 Blue
Microsoft released an application "Preview for Developers" two months ago. This app allows you to install the update GDR3. I think, application changes the update server. If we can decompile application, we will be able to build your own application with this feature. And then we are left to guess the correct update server that stores the update 8.1 Blue. I'm sure this update has testers and they receive it from the server. What do you think about it?