How to change the name of an android app which is displayed in the settings menu?

I want to rename my app and I could change the title / homescreen name via android:label="@string/app_name" in the manifest file. So far so good.

But: in the settings the old name still appears. I’ve tried to change

• the application id in build.gradle
• rootProject.name in settings.gradle
• the package name in the manifest

I’ve also tried clean project and invalidate caches in Android Studio

Where does android derive the name displayed in the settings from? Do I have to clear some other caches? Is this a bug in older Android versions? What am I missing?