I have created a table for that to provide you all this information in an screenshot from MVC 2 to MVC 6.
| MVC 2 | MVC 3 | MVC 4 | MVC 5 | MVC 6 |
| Provide Client side validations | New Project Templates with HTML5 and CSS3 Support | ASP.NET Web API | ASP.NET Identity | ASP.NET MVC and Web API has been merged in to one |
| Asynchronous Controller | Improvised Model validation | Adaptive rendering for look and feel | Authentication Filters for authenticating user by custom or third-party authentication provider | Optimized for Cloud Computing |
| Html.ValidationSummary Helper Method | Supports Multiple View Engines | Mobile Project Template Based on jQuery Mobile | Bootstrap in the MVC template | side by side deployment |
| DefaultValueAttribute in Action-Method Parameters | Razor View Engine with new features | Enhanced support for asynchronous methods | Filter overrides | vNext is Open Source |
| Binding Binary Data with Model Binders | ViewBag dynamic property and ActionResults Types | DotNetOpenAuth library | | JSON-based project Extension |
| DataAnnotations Attributes | new IDependencyResolver for DI | | | Roslyn compiler for dynamic compiling |
| New RequireHttpsAttribute Action Filter | Model Validation Improvements | | | |
| Templated Helpers | Partial page output caching | | | |
| Display Model-Level Errors | | | | |
| Areas | | | | |
| Model-Validator Providers | | | | |
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