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Customer Feedback and No Viable Replacement Forces Cancellation of Mailbox External Recipient Rate
In an unexpected development, the Exchange product group announced in a January 6 EHLO blog post that they have decided to cancel the introduction of the mailbox external recipient rate limit (MERR). Originally proposed in April 2024, Microsoft planned to introduce the new mailbox restriction of being able to send email to 2,000 external recipients over a 24-hour sliding window in January 2025. Following customer pushback, Microsoft subsequently changed the introduction date to April 2026.
Given the wording of the announcement, it seems clear that the level of customer pushback increased as organizations figured out what effect a 2,000 limit would have on their operations. Although Microsoft is quite clear that Exchange Online is not designed to handle bulk email, there’s no doubt that many tenants send communications to external recipients that come perilously close to bulk email. I guess that one person’s highly specific and precise marketing monthly update is another person’s spam.
The tenant-level External Recipient Rate Limit and the overall mailbox recipient limit remain in place and are unaffected by the cancellation.
Make Exchange Online Less Attractive to Spammers
The idea between a mailbox external rate limit is simple. If people can’t send more than 2,000 external emails over a 24-hour period, Exchange Online becomes a lot less friendly for spamming operations. Although some Microsoft decisions seem to be made in a perfect vacuum, I know that telemetry showed that not many mailboxes would fall foul of the limit.
However, the problem is that some of the mailboxes that would be affected send important messages that are incorporated into business processes. A decision to limit spamming also affects how organizations work and their communication with their customers and partners, and that’s unacceptable. Any change made that removes functionality that people depend on is intolerable unless an adequate replacement is available.
No Immediate Replacement for Small-Scale External Email Communications
The problem Microsoft has is that they can’t offer a replacement that allows tenants to send relatively small amounts of external email. The alternative is to use Email Communication Services (ECS), part of the Azure Communication Services (ACS) solution. ECS is built on top of the Exchange Online platform and is absolutely capable of sending very large quantities of external email. That is, after all, what Microsoft designed ECS to do.
However, setting up external email transmission through ECS is not easy for non-technical users. When I last looked at ECS in 2024, it took a considerable number of complicated steps and PowerShell to send email to a bunch of external recipients. Add in the requirement to pay for Azure processing, and you can see why customers are unimpressed by this option.
The ECS experience is definitely nowhere close to using Outlook to compose and send a message to a distribution list. Exchange users have been accustomed to this very simple and straightforward task for many years. Asking them to change to a dramatically different approach introduces a heap of friction into a task that should take just a few seconds.
The HVE Conundrum
Microsoft’s options were limited when they decided to remove the capability to send remote email from its High-Volume Email (HVE) solution. HVE originally could send a limited number of external messages daily, but Microsoft changed its strategy to reposition HVE as an internal email solution for email communications, including email sent by applications and devices such as printers and scanners.
The latest date for general availability of HVE is March 2026, but a quick glance through the comments for Microsoft’s post announcing that date shows that many challenges still exist.
A Good Call to Cancel the Mailbox External Recipient Rate Limit
I think Microsoft was right to reverse course. Pressing ahead with a feature that would do some goodness at the expense of potentially upsetting many customers doesn’t seem like a good strategy. It would have ended in tears of frustration and probably some heated discussions between customers and Microsoft account teams. Dumping the external recipient rate limit for mailboxes was a good idea. Without a no-cost and easy alternative for customers to use, imposing a limit on the external email that individual mailboxes could send would never fly.
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I really wish they would introduce a reasonable solution for mass-emails that are legitimate business communications, but look spammy in the right light. We tend to run into this with communications with a large number of residents (as a local government, and many things that citizens want to receive email updates around), and with year-end updates of meetings with a huge number or participants.
None of our 3rd party options quite fit the bill either, as these are reserved for “opt-in, link to unsubscribe” situations only, which is not really the case for required communications or emails related to boards, committees and commissions that the citizen has “opted in” to.
Joking apart given my comments in this article, ECS might be a good solution for you.
This makes me happy. The organization I work for has a thing where we have a yearly price fee for the companies that we deal with. Those renewal notices go out at the same time, to about 38,000 companies/customers. Those notices go out over the course of 5 days, once per year.
This would have really screwed us over, but only for one week per year when those notices would have needed to go out. We didn’t want to have to subscribe to another product and get it working for a thing we need literally once.
I also support the cancellation. Just imagine that a customer comes from an on-premises environment where he was never restricted by any limits. Now being on a fee-based tenant, he will simply not understand Microsoft’s restriction.