I created a new project in Visual Studio for the last proposed version 12, then I changed the asp.net version to 8 and updated the Umbraco package to 13.1.0.
If I try to run the project I get the following error:
BootFailedException: Boot failed: Umbraco cannot run. See Umbraco's log file for more details.
Umbraco.Cms.Core.Exceptions.BootFailedException.Rethrow(BootFailedException bootFailedException)
Umbraco.Cms.Web.Common.Middleware.BootFailedMiddleware.InvokeAsync(HttpContext context, RequestDelegate next)
Microsoft.AspNetCore.Builder.UseMiddlewareExtensions+InterfaceMiddlewareBinder+<>c__DisplayClass2_0+<<CreateMiddleware>b__0>d.MoveNext()
SixLabors.ImageSharp.Web.Middleware.ImageSharpMiddleware.Invoke(HttpContext httpContext, bool retry)
Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddlewareImpl.Invoke(HttpContext context)
The error in the Umbraco log is the same.
This is a companion discussion topic for the original entry at https://our.umbraco.com/forum/113478-clean-umbraco-1310-wont-run