Can you still create v1 apps by upgrading to new Ionic CLI?

I am curious if I upgrade my current version of Ionic CLI (currently using 5.4.13) to the newest @ionic/cli version if I will still be able to edit and maintain my v1 apps along with create new v4/v5 apps?

Thanks for any info or pointing me in the best direction to answer my question.

Yes, the Ionic CLI is backward compatible.

npm i -g @ionic/cli@latest

Do you have to choose Cordova at the time of the upgrade, or can you choose Cordova/Capicator on a per project basis?

You choose either, on a per project basis.