Voicemail notifications

Voicemail notification works fine, maybe a little too fine. Is there a trick to stop voicemail notifications for old messages that have been played and moved to a different folder without having to delete messages I want to keep? Old messages are displayed as new voicemails on handset, and sends a new notification anytime signal drops and device has to reregister or switching between wifi and mobile data. Thanks in advance.

FreePBX 16.0.33 with Zoiper on Android.