Android PlayStore warning your app currently targets API level 25

This is because Google has made it compulsory for apps to target at least 26 API level by August 2018 for new apps and November 2018 for updating apps.

Docs here.

You can update your cordova-android to 7.0.0 as that's the version that uses SDK 26 as target, or you can update to cordova-android 7.1.4, as it targets SDK 27.

You can do it by removing the platform and adding it again specifying the version to use like this: (if not using ionic, remove the ionic word from both commands)

ionic cordova platform rm android
ionic cordova platform add [email protected]

If you don't want or can't update, you can try to set the target SDK with this preference in the config.xml

<preference name="android-targetSdkVersion" value="26"/>

And then run ionic cordova prepare