Hello, I just recently learning .NET and Umbraco for a few months for our client project. Currently try to do a minor upgrade from Umbraco 8.11.1 to latest version Umbraco 8.18.7 using manual upgrade (zip file) in a dummy project.

I follow the instruction from the documentation on minor upgrade for Umbraco 8 but got a server error when running the project instead of getting installer. Any suggestions how to solve it?

The documentation link: https://docs.umbraco.com/umbraco-cms/fundamentals/setup/upgrading/version-specific/minor-upgrades-for-umbraco-8#finalize

Stack Trace:

[NullReferenceException: Object reference not set to an instance of an object.] Umbraco.Web.Runtime.WebRuntime.Boot(IRegister register) in D:\a\1\s\src\Umbraco.Web\Runtime\WebRuntime.cs:55 Umbraco.Web.UmbracoApplicationBase.HandleApplicationStart(Object sender, EventArgs evargs) in D:\a\1\s\src\Umbraco.Web\UmbracoApplicationBase.cs:65 Umbraco.Web.UmbracoApplicationBase.Application_Start(Object sender, EventArgs evargs) in D:\a\1\s\src\Umbraco.Web\UmbracoApplicationBase.cs:74

[HttpException (0x80004005): Object reference not set to an instance of an object.] System.Web.HttpApplicationFactory.EnsureAppStartCalledForIntegratedMode(HttpContext context, HttpApplication app) +475 System.Web.HttpApplication.RegisterEventSubscriptionsWithIIS(IntPtr appContext, HttpContext context, MethodInfo[] handlers) +118 System.Web.HttpApplication.InitSpecial(HttpApplicationState state, MethodInfo[] handlers, IntPtr appContext, HttpContext context) +176 System.Web.HttpApplicationFactory.GetSpecialApplicationInstance(IntPtr appContext, HttpContext context) +220 System.Web.Hosting.PipelineRuntime.InitializeApplication(IntPtr appContext) +303

[HttpException (0x80004005): Object reference not set to an instance of an object.] System.Web.HttpRuntime.FirstRequestInit(HttpContext context) +659 System.Web.HttpRuntime.EnsureFirstRequestInit(HttpContext context) +89 System.Web.HttpRuntime.ProcessRequestNotificationPrivate(IIS7WorkerRequest wr, HttpContext context) +189