Don't export CoreReceiver

        <receiver

            android:name=".service.CoreReceiver"

            android:enabled="true">

            <intent-filter>

                <action android:name="com.fsck.k9.service.CoreReceiver.wakeLockRelease"/>

            </intent-filter>

        </receiver>

            android:exported="false"/>

        <receiver

            android:name=".service.StorageReceiver"