a friend's interview question

A friend was texting me yesterday about an interview she had in which she was asked how she would get an Angular 7 component working in an Angular 2 application. Unless I am missing something, I imagine there is no guarantee that one wouldn't have to do some rewriting to get out actor afloat. Things like the email keyword to validate email addresses and the else case for an *ngIf (both showed up with Angular 4) cannot work in Angular 2 and that's just scratching the surface to say nothing of Angular Materials (showed up with Angular 6). I supposed you could put the component where you wanted it, run the application, and then try to deal with the red being barfed up to the console by way of progressive little stitches of rewriting.