We are developing ASP.NET MVC application. We are using a latest version of the frameworks. So I need to update a software after each framework's upgrade. It easy to do on the developer's machine: you can use web or standalone installer or nuget package. Usual I used to run installer on the server for the previous version of ASP.NET MVC. But I noticed that installer for ASP.NET MVC 4 contains SQL Express Server and Visual Studio Express 2012 for Web. They are definitely not tools for the server's PC. I carried on with googling and found out that ASP.NET MVC 4 doesn't need any extra library in GAC. It requests .NET Framework (4 or 4.5) on the server and it all. I deployed my latest (created as ASP.NET MVC 4) project on the server and it run without any concerns. But when I deployed 'migrated' project, it was crashed. I checked log file and found that latest (ASP.NET MVC 4) libraries weren't included.