I concur with Brenden. I did this (but don't have any documentation), but basically making the necessary changes to the web.config and upgrading the connection to the .net 4.5 DLLs does the trick. The only situation you would have to worry about is any custom DLLs you have released. As long as they are tied to 4.0 then you should be fine because 4.5 is backwards compatible, but if you are using any of the 3.5 stuff (whcih 4.0 was backwards compatible with) you may run into some issues.