Me and my colleagues got a commercial, yearly, JetBrains license and we are running ReSharper 9.0.1 in VS2013. Today ReSharper stopped working with the message that it couldn't find a valid license for our product. When I login to the management page I see that we have a license for 9.1.
Is it not possible to use a 9.1 license running 9.0.1? Or to put it differently: are we forced to upgrade with every new version?