Gmail has sorted marketing mail into its own tab since 2013. Business inboxes on Outlook never had an equivalent, which is part of the reason why B2B senders spent the better part of a decade hoping their newsletter landed somewhere near the CFO’s calendar invites.
This fall marks the end of that. Microsoft now labels every bulk message it detects as “Promotions” in Outlook on the web and Outlook for Windows, and its documentation says the feature should be available in all Exchange Online organizations by mid-September. This is the biggest of the four stories we’ll cover this month, and all four have something in common: each one takes away something the sender used to be able to see.
Key takeaways
- Outlook on the web and Windows tag all bulk mail as Promotions, regardless of its complaint score. That mail is moved into a separate folder automatically only when a recipient-side setting called “Bulk moves enabled” is switched on.
- The Promotions folder learns from users. Moving a sender in or out changes where that sender’s future messages land for them.
- New Microsoft 365 tenants now face sending limits. Microsoft began cutting trial tenants to 500 external recipients a day on September 14th. Tenants under 31 days old get 10% of their normal quota.
- iOS 27 lets users on Apple Intelligence-capable iPhones ask Siri to delete every email from a sender, which removes a subscriber without an unsubscribe or a complaint.
Outlook builds the tab Gmail has had for thirteen years
As of July 2026, every message Exchange Online identifies as bulk gets the “Promotions” tag regardless of its bulk complaint level (BCL), the score Microsoft assigns based on how complaint-prone a bulk sender seems to be — though the tag itself appears only in Outlook on the web and Outlook for Windows. The label is where the similarity ends: a newsletter with a spotless BCL of 0 carries the same tag as a careless blast, but mail at or above the BCL threshold is delivered to Junk or quarantined, while only mail below the threshold is eligible for the Promotions folder.
The tag and the folder are different mechanisms. The tag is a label. The folder physically moves mail out of the inbox, and it does that automatically only when “Bulk moves enabled” is switched on in the recipient’s anti-spam policy. Whether your webinar invite ends up in a Promotions folder therefore depends on an IT decision inside someone else’s company that you will never see.
The tag works as a condition in Outlook inbox rules, so any user can build a rule that routes tagged mail into a folder or deletes it altogether. And according to Microsoft Learn, the system learns as users move messages into and out of the folder.
That learning changes a lot for B2B programs, which up until now have mostly been judged based on authentication and complaint rates inside corporate filters. Now each recipient’s own habits decide where your mail lands for them.
New Microsoft tenants are on a sixty-day probation
Microsoft also reduced how much mail new tenants can send outside their own domains. The Tenant External Recipient Rate Limit (TERRL) limits how many external recipients an entire Exchange Online tenant can reach in a rolling 24 hours. Changes announced in an August 13 Exchange Team update began rolling out on September 14th, with no completion date published:
- Trial tenants are limited to 500 total external recipients per day, regardless of how many trial licenses are added.
- Tenants younger than 31 days receive 10% of their standard quota.
- Tenants between 31 and 60 days old receive 25%.
Microsoft framed the change as abuse prevention and did not mention cold email. Setting up disposable Microsoft 365 tenants for outreach used to be cheap and fast. Nely Bonar, co-founder of emailexpert, wrote that the rules could encourage senders to stockpile tenants and create a “secondary market for aged tenants.”
For ordinary businesses, the risk is that the limit applies to the whole tenant. A sales department that uses up the allowance on a prospecting campaign stops external mail for everyone, including invoices and other important mail, with each blocked message returning a 550 5.7.233 bounce (trial tenants get 5.7.232 instead).
Microsoft’s own filtering can also malfunction. As reported by emailexpert, Microsoft attributed more than six hours of delays on September 4th to enforcement of a specific anti-spam model, affecting mail involving external domains, with senders receiving temporary “451 4.7.500 Server busy” responses. Microsoft later added affected sending IPs to an allow list while it disabled the model. Retried mail eventually got through, while any setup that treats 4xx errors as final would have dropped messages Microsoft never meant to reject.
iOS 27 turns unsubscribing into a sentence
Apple released iOS 27 on September 14th, and its Mail app gained a Siri capability that marketers should know about. According to MacRumors, users can ask Siri to delete all emails from a specific sender. During the summer beta, 9to5Mac noted a user sharing the trick on social media as a way to deal with senders spamming them.
Senders get no signal when it happens. There’s no unsubscribe request to process and no complaint arriving through a feedback loop. The subscriber clears the inbox in one sentence, the sender’s list still counts them as active, and the next several campaigns go to someone who has already tuned out.
Search changes for every iPhone on iOS 27, with or without Apple Intelligence. Mail now ranks results by relevance and intent instead of keywords and recency. In practice a search for a retailer can now surface a recent order ahead of that retailer’s promotions, so marketing mail competes with a subscriber’s own transaction history for attention.
The Siri features are limited for now, requiring an iPhone that supports Apple Intelligence. Siri AI also isn’t available in the EU or China at launch.
AI agents get their own outbox
On September 23rd, Bird launched Agentic Harness, giving AI agents direct access to its email, messaging, and voice infrastructure. Bird says the harness lets agents send and manage email through its network, with tools such as ChatGPT, Codex, and Cursor connecting through a Model Context Protocol (MCP) server, according to IO+.
The harness is positioned for agents acting on a company’s behalf rather than for human senders, as reported by PYMNTS.
For deliverability, the implication is that a growing share of business email may soon be composed, timed, and sent by software acting on a company’s behalf. Mailbox providers will judge that mail the same way they judge everything else, by how recipients respond. An agent that sends at volume to people who never engage creates the same reputation damage a careless marketer would, only faster.
What comes next
The Promotions folder is still opt-in for admins, but the tag already appears on every bulk message in Outlook on the web and Windows. Microsoft’s documentation reminds users that future placement follows what users do with that mail, so the way to keep a campaign out of the folder is to have recipients treat it as mail they want.
InboxAlly tracks inbox placement across its own mailboxes, and reports primary-inbox placement separately from placement that includes Promotions, so a shift between the two shows up instead of hiding inside a single number. Start a free trial and build engagement on your real campaigns.