Confused about rxjs operator imports

I have updated the imports for rxjs operators in my project so that they now conform to the new recommended syntax, such as:

import { switchMap, debounceTime }          from 'rxjs/operators';

However when I try to follow the same pattern for the "do" operator, TypeScript complains when I build my code. In order to get it to work, I need to use the older syntax pattern such as:

import 'rxjs/add/operator/do';

Am I doing something wrong or is the older pattern still needed for the "do" operator?

Thank you!