Where to begin?
OS Where Upgrade is being done:
Version: Windows 10 IIS 10
Note: IIS and the OS are configured according to instructions found on Progress Sitefinity site.
Here's the link to the steps I'm following: http://docs.sitefinity.com/upgrade
I had endless problems with these instructions but eventually figured things out on my own.
Note: These instructions are missing key instructions.
I eventually figured out that I have to change the Target Framework of the project for it to build correctly. Once I got this right I was able to successfully run it in a browser up to the point where it says success but when I then clicked Go To Site i got this:
Could not load file or assembly 'Telerik.Sitefinity, Version=7.3.5610.0, Culture=neutral, PublicKeyToken=b28c218413bdf563' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)
I've searched everywhere for a reference to that version of the assembly and I can't find it. Somehow somewhere this version of the assembly is being referenced, but I can't find where!