I just upgraded to 7.4 today from 7.2 (using nuget) and I'm getting the following error (code worked fine in 7.2):

Cannot bind source content type Umbraco.Web.PublishedCache.XmlPublishedCache.XmlPublishedContent to model type Models.Auth.LoginModel

Umbraco.Web.Mvc.RenderModelBinder.BindModel(Object source, Type modelType, CultureInfo culture) +551

Heres my Model:

public class LoginModel : Umbraco.Core.Models.PublishedContent.PublishedContentModel
{
    public LoginModel() : this(new UmbracoHelper(UmbracoContext.Current).TypedContent(UmbracoContext.Current.PageId)) { }
    public LoginModel(IPublishedContent content) : base(content) { }

    [Required]
    [MaxLength(100)]
    public string Email { get; set; }

    [Required]
    [MaxLength(100)]
    public string Password { get; set; }

    [MaxLength(500)]
    public string RedirectUrl { get; set; }
}

and Its a regular post on my auth surface controller:

    [HttpPost]
    public ActionResult HandleLogin(Models.Auth.LoginModel loginModel)

Any advice? Does this method for building models still work in 7.4, or should I be trying out the new Models Builder?

Noticed there is an updated DLL in another thread, I'll give that a try too.