A lighter-weight roundup of the email deliverability headlines that mattered this quarter, drawn from ISP announcements and industry reporting — not our own benchmarks this time.
Gmail moved from "soft" to full enforcement. After nearly two years of warnings, Google began actively rejecting non-compliant bulk mail in November. The grace period is over: senders without aligned SPF, DKIM, and DMARC are seeing bounces, not just spam-folder placement.
The Google and Yahoo bulk-sender rules are now just "the rules." One-click unsubscribe (RFC 8058), authenticated sending domains, and low spam-complaint rates (Gmail's 0.3% threshold is the number everyone quotes) have shifted from best practice to table stakes.
Microsoft is aligning. Outlook / Hotmail / Live have been tightening their own requirements through the quarter, narrowing the gap with Google and Yahoo. Expect 2026 to be the year where most senders stop maintaining separate playbooks per mailbox provider.
BIMI keeps gaining ground. It's not required, but more mailbox providers are displaying brand logos when DMARC is fully enforced — and deliverability teams are treating it as a visibility lever rather than a nice-to-have.
List hygiene is doing more heavy lifting than ever. With complaint thresholds being enforced in real time, the cost of stale or purchased lists has gone up sharply. Senders that invested in consent quality and re-engagement strategies this year are the ones still hitting the inbox.
What we're watching next quarter
- Broader DMARC enforcement from secondary ISPs
- How "revocation-all" delays in the SMS world spill back into cross-channel suppression practices
- Continued consolidation of authentication requirements across providers
The takeaway
This wasn't a quarter about shiny new tactics. It was a quarter about the fundamentals — authentication, hygiene, engagement — getting teeth. Senders who'd already done the work kept deliverability flat or up; senders who hadn't felt it in their numbers.
