Yes. The Cisco Meraki MX Security Appliance uses Dynamic DNS (DDNS) to update its DNS host record automatically each time its public IP address changes.
The Dynamic DNS updates automatically to whatever Public IP the MX is using, but it can take about 10mins go update as per this:
Note:The expected TTL for dynamic DNS records is typically about 10 minutes, so you may need to wait 10 minutes before testing to see accurate results.