Should I upgrade and is Ionic 1 still viable?

I have several apps that were developed using Ionic 1. I wondering if it is really necessary to move up to Ionic 3+. I am still using Angular 1 in most of my development and have not made the switch. I need to do some updates to my app and want to get some sense of whether or not it is worth the hassle to update to Ionic 3/4?

Is Ionic 1 still being maintained with security updates etc?

Thanks,

RGecy

No input on this? Suggestions?