Kentico Code Upgrade Tool

Trying to upgrade from Kentico 9 to 10. https://docs.xperience.io/k10/installation/upgrading-to-kentico-10/upgrading-custom-code Enabled Deployment mode and am getting an error on the first step.

CodeUpgrade.exe C:\inetpub\wwwroot\Kentico9\WebSite.sln

I added a reference to Tasks.Dataflow to see if that would help and it did not. I'm getting this.

! There were multiple errors. ! Exception: One or more errors occurred. ! Stack trace: at System.Threading.Tasks.Task.ThrowIfExceptional(Boolean includeTaskCanceledExceptions) at System.Threading.Tasks.Task1.GetResultCore(Boolean waitCompletionNotification) at System.Threading.Tasks.Task1.get_Result() at Kentico.CodeUpgrade.SolutionUpgrade.ExecuteInternal(String solutionFilePath) at Kentico.CodeUpgrade.SolutionUpgrade.Execute(String solutionFilePath)

! Unknown error. ! Exception: Could not load file or assembly 'System.Threading.Tasks.Dataflow, Version=4.5.24.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The system cannot find the file specified. ! Stack trace: at Microsoft.Build.BackEnd.Logging.LoggingService.ProcessLoggingEvent(Object buildEvent, Boolean allowThrottling)

Any help would be appreciated!