Do the synchronized contacts remain in the Android phonebook after restarting the device?

Yes, once the contacts have been synchronized at least once by the sync.blue® app for Android into the device's local phonebook, these contacts will remain stored offline in the phonebook even after restarting the Android device. This means that the contacts are available locally on the device regardless of an active internet connection or reopening the app. Even if the device is completely powered off and turned back on, the synchronized contacts are not lost and remain available to the user as usual.