On May 20, 2026, the Internet Engineering Task Force published RFC 9989, formally replacing the 2015 DMARC specification and moving the protocol from an informational document to an official Internet Standards Track designation. For businesses, marketers, and growth teams, this shift carries direct implications: the rules governing how your emails are authenticated, delivered, and protected from impersonation just received their most significant update in over a decade.
What RFC 9989 Actually Changes
RFC 9989 is a Standards Track document published in May 2026. It obsoletes both RFC 7489 and RFC 9091, and is a product of the IETF community with approval from the Internet Engineering Steering Group. The update is part of a three-document release. The updated specification, known as DMARCbis, is split into three dedicated documents: RFC 9989 covers the core DMARC mechanism, and RFC 9990 governs aggregate reporting.
This is not a major redesign. The protocol works largely the same way, DMARC records still begin with v=DMARC1, and most domain owners will not need to change existing policies. RFC 9989 primarily clarifies terminology, tightens definitions, and standardizes behavior that had previously been implemented inconsistently.
The most technically significant change is how receiving servers determine your organizational domain. RFC 9989 replaces the Public Suffix List approach with a DNS Tree Walk algorithm, which affects both DMARC policy discovery and identifier alignment under relaxed settings. Under RFC 7489, implementations used a Public Suffix List to determine the organizational domain, but the RFC did not mandate a specific source or update strategy, resulting in inconsistent behavior across implementations.
Despite how comprehensive this update is, DMARCbis introduces no breaking changes. The new tags and revised rules are built so that servers running the legacy standard can safely ignore them without errors.
Why Formalization Matters for Email Deliverability
The move to Standards Track is not just administrative. With RFC 9989, DMARC has officially achieved IETF Proposed Standard status. In practice, this means mailbox providers worldwide will interpret and implement the protocol more consistently, with clearer definitions, better examples, and more actionable guidance for administrators.
