RxJava library functions import issue

[TaraAndroid]

I have downloaded project. It gives me Rx java import issues all over the project. Do I need to implement rx java library in project? below are few import issues listed error: package rx.functions does not exist import rx.functions.Action1;

import rx.Observable; import rx.Subscription; import rx.functions.Action1; import rx.subscriptions.CompositeSubscription;

etc.

I have implemented "implementation 'io.reactivex.rxjava2:rxjava:2.2.7'" . even though does not works. Please suggest what to do.