Yes, the user can turn the alarm sound off and use the alarms in vibration mode only in the FreeStyle Libre apps^34,35.

For the optional alarms^619,18 on your FreeStyle Libre  apps^34,35, you can set them to vibrate-only by turning OFF " Override Do Not Disturb" and setting your phone to vibrate-only, or turning on Silent Mode³²⁰.

When "Override Do Not Disturb" is OFF, the FreeStyle Libre apps^34,35 will follow your smartphone's volume and vibration settings.