(Source of this article is MSDN)
Attribute routing improvements
Attribute routing now supports constraints, enabling versioning and header based route selection. Many aspects of attribute routes are now customizable via the IDirectRouteFactory interface and RouteFactoryAttribute class. The route prefix is now extensible via the IRoutePrefix interface and RoutePrefixAttribute class.
Enum support in views
a) New @Html.EnumDropDownListFor() helper methods. These should be used like most of the HTML helpers with the caveat that the expression must evaluate to an enum type or a Nullable where T is an enum type. UseEnumHelper.IsValidForEnumHelper() to check these requirements.
b) New EnumHelper.GetSelectList() methods which return an IList. This is useful when you need to manipulate a select list prior to calling, for example, @Html.DropDownList (), or when you wish to display the names which @Html.EnumDropDownListFor() shows.
Bootstrap support for editor templates
It is now allowed to pass HTML attributes in EditorFor as an anonymous object.
For example:
@Html.EditorFor(model => model, new { htmlAttributes = new { @class = "form-control" }, })
Unobtrusive validation for MinLengthAttribute and MaxLengthAttribute
Client-side validation for string and array types will now be supported for properties decorated with the MinLength and MaxLength attributes.
Supporting the ‘this’ context in Unobtrusive Ajax
The callback functions (OnBegin, OnComplete, OnFailure, OnSuccess) will now be able to locate the invoking element via the this context. For example:
@Ajax.ActionLink("Click me", "AjaxAction", new AjaxOptions { UpdateTargetId = "foo", OnBegin = "OnClick" })
The Web MVC project templates integrate seamlessly with the new One ASP.NET experience. You can customize your MVC project and configure authentication using the One ASP.NET project creation wizard.
The MVC project templates have been updated to use ASP.NET Identity for authentication and identity management.
Authentication filters
Authentication filters are a new kind of filter in ASP.NET MVC that run prior to authorization filters in the ASP.NET MVC pipeline and allow you to specify authentication logic per-action, per-controller, or globally for all controllers. Authentication filters process credentials in the request and provide a corresponding principal. Authentication filters can also add authentication challenges in response to unauthorized requests.
Filter overrides
You can now override which filters apply to a given action method or controller by specifying an override filter. Override filters specify a set of filter types that should not be run for a given scope (action or controller). This allows you to configure filters that apply globally but then exclude certain global filters from applying to specific actions or controllers.