DMARC in 2026: What the New RFC 9989 Standard Changes for Email Deliverability
In May 2026, RFC 9989 replaced the original DMARC specification (RFC 7489) and put DMARC on the IETF Standards Track for the first time. The update changes how records are written and read, swaps the pct sampling tag for a new test mode, and adds subdomain tags. Here is what changed, what it means for your DNS, and how to upgrade safely.