Is it necessary for converting all angularjs controllers into angularjs components(v1.5+) for making the hybrid app work?

I have a pretty large AngularJS(v1.5) application which contains numerous controllers. I want to migrate the app to the latest Angular version(v7) using the upgrade module which runs both the old and the new frameworks together, allowing for an incremental approach to the upgrade. So my question is, do I need to convert all my controllers into component directives(introduced from v1.5+) before using the upgrade module to make my hybrid app work? Or can we first make the hybrid app with the controllers as it is and then convert each angularJS controller into angular components?

Another question related to the hybrid approach, the new files which I have been creating(related to the angular framework) are in typescript format. Do I need to convert all the old javascript files into typescript to make the hybrid app work?

Source: AngularJS