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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