I started doing the Safeharbour projects years ago and at the time I decided to use the relatively new Ionic Framework to get the job done. It used Angular 1.0 and as I liked the idea of hybrid apps for a project like this, getting 'the website for free' had some appeal to this small operation.
Well if you're familiar with Ionic, today its at version 5, supports more than just angular, and is phasing out Cordova for its own home written Capacitor. I'll get back to that...
So these apps started as Ionic 1 apps with Angularjs 1. Then Angular 2 happened, and we don't need to go into the incompatibilities and drastic syntax changes involved there. But the Safeharbour apps are small simple things, so upgrading them wasn't much of a problem. But profesionally I work with ServiceNow, and ServiceNow had bought into Angularjs as well... so I couldn't just forget about it! I still had to use it most every day since the ServiceNow Portal is (still) written in it.
Ionic and Angular kept moving onwards, and I tried to keep up, but the Safeharbour apps don't exactly need the latest and greatest technology to stay relevant, so as of today they are sitting with Angular 5 and Ionic 3.9.2, and are likely to stay there for the forseeable future.
Food 4 NY however was a new project, so I started it from scratch with the 'latest and greatest'. Except Ionic 5 was out and was touting its compatibility with ReactJS, which I didn't know, and I didn't really understand what Electron or Capacitor were or why I would want to use them over Cordova. So many technologies doing 'the same thing', and so little time to keep up. So Food 4 NY is using Angular 9 and Ionic 5 with Cordova.
So I now actively work with and maintain code in Angular 1, 5, and 9 and apps using Ionic 3 and 5. It's truthfully a lot to keep straight sometimes. ServiceNow may be embracing React in the future however, and as I'm happy with Ionic and it also can be used with React, maybe it's time to drop Angular and simplify my life a bit.