Yes, DMARC is now mandatory due to 2024 requirements from major mailbox providers:

• Gmail and Yahoo require at minimum a DMARC policy of "p=none"

• Recommended DMARC Implementation Process:

  1. Start with "p=none" for at least one week

  2. Monitor reports and fix any authentication issues

  3. Gradually progress to "p=quarantine" following Gmail's recommended rollout plan

  4. Eventually move to "p=reject" for maximum protection

For detailed guidance, review Gmail's DMARC rollout recommendations.