How to fix Expected Android API level 21+ but was 19 in Android

Question

In my application i want get data from server, for get connect to server i used Retrofit, OkHttp.
But when running application, show me

Answer 1

Note for @Anupam answer - force is deprecated if you are using Android Studio 4.0+

https://docs.gradle.org/current/userguide/upgrading_version_5.html

Forced dependencies Forcing dependency versions using force = true on a first-level dependency has been deprecated.

Force has both a semantic and ordering issue which can be avoided by using a strict version constraint.

the way ahead is to use the keyword "strictly" for dependency downgrade. refer to https://docs.gradle.org/current/userguide/dependency_downgrade_and_exclude.html#sec:enforcing_dependency_version

So you should end up with some thing like the following...

  implementation ('com.squareup.okhttp3:okhttp'){ 
            version {
                strictly '3.12.12'
            }
    }