https://email-spam-tester.com/blog/email-deliverability-news/What changed at Gmail, Yahoo, Microsoft and the standards bodies, and what to check.enhttps://email-spam-tester.com/blog/email-deliverability-news/#exchange-online-tenant-limit-new-trial-eduhttps://email-spam-tester.com/blog/email-deliverability-news/#exchange-online-tenant-limit-new-trial-eduSat, 31 Oct 2026 12:00:00 +0000From September 14, 2026 young tenants get a fraction of their external recipient quota, and trial tenants are held to 500 recipients a day. Who is affected: New Microsoft 365 tenants, trial tenants and schools on free Education licenses. What to check: Check your tenant's age and licenses before a large send. Search bounces for 550 5.7.232 and 550 5.7.233. Send bulk mail through a service built for it. Source: https://techcommunity.microsoft.com/blog/exchange/introducing-exchange-online-tenant-outbound-email-limits/4372797https://email-spam-tester.com/blog/email-deliverability-news/#m3aawg-legally-mandated-emailhttps://email-spam-tester.com/blog/email-deliverability-news/#m3aawg-legally-mandated-emailThu, 17 Sep 2026 12:00:00 +0000Version 2.0 of the M3AAWG guide covers breach notices, recalls and court-ordered mail that has to reach people who opted out long ago. Who is affected: ESPs and companies sending breach notices, recalls or court-ordered mail. What to check: Send from a recognisable subdomain of your own domain. Configure SPF, DKIM and DMARC. Mail impacted users first and bounced addresses last. Source: https://www.m3aawg.org/sites/default/files/doc_files/m3aawg-best-practices-for-sending-legally-mandated-emails-to-large-audiences.pdfhttps://email-spam-tester.com/blog/email-deliverability-news/#m3aawg-sender-best-practices-v4https://email-spam-tester.com/blog/email-deliverability-news/#m3aawg-sender-best-practices-v4Thu, 17 Sep 2026 12:00:00 +0000Version 4.0 replaces the 2011 and 2015 documents, with more on address collection, domain warming and being transparent about data. Who is affected: Senders warming a new domain or subdomain, and the ESPs that host them. What to check: Warm a new domain over about six weeks and spread each day's volume. Warm a new subdomain too. Stay away from artificial warming services. Source: https://www.m3aawg.org/sites/default/files/doc_files/m3aawg-sender-best-common-practices-aug-27-2026.pdfhttps://email-spam-tester.com/blog/email-deliverability-news/#dmarc-rfc-9989https://email-spam-tester.com/blog/email-deliverability-news/#dmarc-rfc-9989Thu, 17 Sep 2026 12:00:00 +0000The DMARCbis documents are out. The pct, rf and ri tags are gone, np, psd and t are new, and a DNS tree walk replaces the Public Suffix List. Who is affected: Every domain with a DMARC record. What to check: Read Appendix A.6 of RFC 9989 if your record carries a partial pct. Use t=y where you relied on pct=0. Consider np for subdomains that don't exist. Source: https://www.rfc-editor.org/info/rfc9989https://email-spam-tester.com/blog/email-deliverability-news/#arc-reclassify-historichttps://email-spam-tester.com/blog/email-deliverability-news/#arc-reclassify-historicThu, 17 Sep 2026 12:00:00 +0000A DMARC working group draft asks to end the ARC experiment, stop relying on ARC between unrelated parties, and move RFC 8617 to Historic. Who is affected: Anyone counting on ARC to carry mail through forwarders and mailing lists. What to check: Don't build new plans around ARC. Keep an aligned DKIM signature on your mail. Source: https://datatracker.ietf.org/doc/draft-ietf-dmarc-arc-to-historic/https://email-spam-tester.com/blog/email-deliverability-news/#m3aawg-tls-baselinehttps://email-spam-tester.com/blog/email-deliverability-news/#m3aawg-tls-baselineThu, 17 Sep 2026 12:00:00 +0000The April 2026 revision of M3AAWG's TLS for Mail recommendations rules out everything older than TLS 1.2 and asks mail operators to log TLS details. Who is affected: People who run their own mail servers. What to check: Offer TLS 1.2 and 1.3 only. Log the TLS version and cipher of each session. Look at DANE or MTA-STS to stop downgrade attacks. Source: https://www.m3aawg.org/sites/default/files/doc_files/tls-for-mail-m3aawg-baseline-recommendations-april-2026_0.pdfhttps://email-spam-tester.com/blog/email-deliverability-news/#spamhaus-oracle-public-mirrorshttps://email-spam-tester.com/blog/email-deliverability-news/#spamhaus-oracle-public-mirrorsThu, 17 Sep 2026 12:00:00 +0000From April 15, 2026, Spamhaus blocklist queries sent from Oracle's network to the public mirrors return 127.255.255.254. The fix is a free DQS key. Who is affected: Mail servers on Oracle's network that use the public Spamhaus mirrors, and anyone who mails them. What to check: If you run a server there, use a free DQS key or a resolver with attributable reverse DNS. Make sure your server doesn't read 127.255.255.254 as a listing. If clean mail bounces with a Spamhaus message, look at the receiver's network too. Source: https://www.spamhaus.org/resource-hub/email-security/querying-the-free-dnsbls-via-oracle/https://email-spam-tester.com/blog/email-deliverability-news/#postmaster-tools-api-v2https://email-spam-tester.com/blog/email-deliverability-news/#postmaster-tools-api-v2Thu, 17 Sep 2026 12:00:00 +0000Google's v2 API exposes the full Postmaster Tools data, compliance status included. The v1 API and the reputation dashboards are on their way out. Who is affected: Teams that pull Postmaster Tools data into their own dashboards or alerts. What to check: Move integrations from the v1 API to v2. Replace alerts built on domain or IP reputation. Watch compliance status instead. Source: https://developers.google.com/workspace/gmail/release-noteshttps://email-spam-tester.com/blog/email-deliverability-news/#exchange-online-smtp-auth-basic-timelinehttps://email-spam-tester.com/blog/email-deliverability-news/#exchange-online-smtp-auth-basic-timelineThu, 17 Sep 2026 12:00:00 +0000Basic authentication for SMTP client submission in Exchange Online will be off by default for existing tenants at the end of December 2026. Who is affected: Printers, scanners, scripts and apps that send through Exchange Online with a username and password. What to check: List everything that submits mail with a password. Move each sender to OAuth, a connector relay or a sending service. Send a test message over the new route before the default changes. Source: https://techcommunity.microsoft.com/blog/exchange/updated-exchange-online-smtp-auth-basic-authentication-deprecation-timeline/4489835https://email-spam-tester.com/blog/email-deliverability-news/#exchange-online-recipient-limit-cancelledhttps://email-spam-tester.com/blog/email-deliverability-news/#exchange-online-recipient-limit-cancelledThu, 17 Sep 2026 12:00:00 +0000The per-mailbox cap of 2,000 external recipients a day, due from April 2026, is cancelled. The 10,000 recipient limit stays in place. Who is affected: Organizations that send to external recipients from Exchange Online mailboxes. What to check: Drop the April and October 2026 dates from your plans. Stay within the 10,000 recipient daily limit and your tenant limit. Move newsletters and bulk app mail to a sending service. Source: https://techcommunity.microsoft.com/blog/exchange/exchange-online-canceling-the-mailbox-external-recipient-rate-limit/4483498https://email-spam-tester.com/blog/email-deliverability-news/#gmail-enforcement-rejectionshttps://email-spam-tester.com/blog/email-deliverability-news/#gmail-enforcement-rejectionsThu, 17 Sep 2026 12:00:00 +0000From November 2025 Gmail answers non-compliant mail with temporary and permanent rejections, where before it mostly filtered or deferred it. Who is affected: Everyone sending to personal Gmail accounts. The stricter rules start at 5,000 messages a day. What to check: Check that your From domain aligns with SPF or DKIM. Keep the Postmaster Tools spam rate under 0.3%. Search your bounce logs for 5xx rejections from Gmail. Source: https://support.google.com/mail/answer/14229414https://email-spam-tester.com/blog/email-deliverability-news/#yahoo-sender-hub-insightshttps://email-spam-tester.com/blog/email-deliverability-news/#yahoo-sender-hub-insightsThu, 17 Sep 2026 12:00:00 +0000Yahoo added Insights to Sender Hub, with delivered volume and spam complaint rate per verified DKIM domain, counted on inbox mail only. Who is affected: Anyone sending to Yahoo Mail who signs with a DKIM domain of their own. What to check: Verify your DKIM domain in Sender Hub and activate Insights. Go by Yahoo's complaint rate, which counts inbox mail only. If your ESP signs with its own domain, set up custom DKIM first. Source: https://blog.postmaster.yahooinc.com/post/798590258207916032/introducing-insights