Version 5.0.1 of PFM is now online. The only thing that has changed since version 5.0 is a temporary fix has been made to allow the auto-update to work again. I believe the fix may require .NET Framework version 4.5 or newer to be installed as opposed to the prior minimum requirement of the .NET Framework version 4.0.
In making the fix to the auto-updater it also became clear that in order to cleanly fix the auto-updater so it can use TLS 1.2 to communicate with SourceForge, PFM will have to move from .NET Framework 4.0 to one of three alternatives: A newer version of the .NET Framework, Mono, or Xamarin. I know that moving to a newer version of .NET or Xamarin would break support for PFM in Windows XP and I don't know for sure about whether Mono supports XP. The advantages of switching to Mono or Xamarin as far as I can tell is that the .NET Framework wouldn't work if we tried to get PFM working on Mac or Linux while Mono and Xamarin do (and with some Total War games working on Mac and Linux, it makes sense to have the mod tools work also). This leads me to wonder, how many people use which operating systems among the PFM userbase so I know which systems I still need to guarantee support for? Regardless of the response, changing the framework PFM runs on will still be a relatively low priority as I learn more about how it works and ensure what is already there doesn't have any bugs hiding in it.