Fixing an iPhone that would not update it's apps

For anyone that knows me they will know that I find working with iPhones perhaps the most infuriating thing.

For some time Shelley's iPhone 6 has not been updating Apps. This was not a problem until she wanted to install the FitBit app to go with her new FitBit Alta HR.

I tried all the non-destructive options on various web sites:
https://www.lifewire.com/iphone-cant-update-apps-fix-4057706
https://www.payetteforward.com/iphone-apps-wont-update-heres-fix/
https://www.igeeksblog.com/cannot-update-apps-on-iphone-or-ipad/

This went on for a couple of evenings, while we had time.
Eventually, after backing up the important content, Shelley rang Apple to get some support.

The thing that they suggested that finally worked was to reset the network settings. Even that had to be done a couple of times.

The various reset options are off of the General menu within settings.
==