emailrules.today

Platform changesMailchimp

Platform ledger

What Mailchimp changed.

Dated and permalinked, which is rare. The catch is scope: these notes cover the API and Transactional (Mandrill). Changes to the marketing app itself are announced inside the product and in help articles with no date on them, which is why this column is short and old.

3 changesverified 2 Aug 2026read from Release notes
YoursNo platform does this for you. One concrete move, then you are done.FYIChanges a number you report or a risk you carry, not today's task list.SharedThe platform covers the mechanical bit. The judgement is still yours.
Announced
FYI

Mailchimp began overwriting campaign_id and outreach_id on orders

What changed: Mailchimp started writing over the campaign_id and outreach_id values on orders to match its own attribution model and the account’s settings, and told integrations that send those values with Add Order or Update Order to deprecate that logic.

Why it matters: If you have ever tried to reconcile platform revenue against the shop’s own numbers and lost an afternoon, this is the shape of change that causes it. The platform, rather than your integration, now decides which message a purchase belongs to. Nothing about the emails changed. The number you report did, and it changed on a date.

Do next: Before comparing this year’s attributed revenue with last year’s, check whether the series crosses 6 December 2024. If it does, you are comparing two different attribution models and the trend line is telling you nothing.

Announced
Shared

Transactional sending domains had to publish DKIM and DMARC

What changed: Mailchimp told Transactional (Mandrill) users that from 15 March 2024 it would enforce new sending domain authentication requirements, citing the Google and Yahoo announcements. Two DKIM CNAMEs — mte1._domainkey and mte2._domainkey, pointing at dkim1.mandrillapp.com and dkim2.mandrillapp.com — plus a DMARC TXT record at _dmarc, for which the note gives the value v=DMARC1; p=none. Domains that did not comply would have their mail sent from a mandrillapp.com subdomain instead, with replies still routed to the original address.

Why it matters: This is the clearest example on the site of a platform doing the mechanical half and leaving the judgement. The record Mailchimp asks for is p=none, which is monitoring: it asks receivers to report and instructs them to reject nothing. A domain that followed this instruction to the letter and then stopped is authenticated as far as the platform is concerned and still unprotected against someone spoofing it. The fallback is worth knowing too — your mail keeps going out, but from a domain that is not yours, which is not what anyone reading the From line expects.

Do next: Read your own _dmarc record today. If it still says p=none and nobody is reading the reports, you completed the platform’s task and not the one that protects you.

Mailchimp changed · these did not

Only changes that touch deliverability, consent, classification or a number you report are listed. Mailchimp ships far more than this; a builder getting a new toolbar is not a change to what is true about your programme. Missing something dated? corrections@emailrules.today.

FAQ

Awkward questions

Who is this actually for?

People who ship email and are too busy to re-read every PDF: week-one marketers, lifecycle/CRM, deliverability, multi-country ops, DTC brands, agencies — on Klaviyo, Mailchimp, Braze, HubSpot, SFMC, or something else. Pick your tool and geos so product-specific pages only appear when they match. EU and UK are first-class filters. Not for people who sell tools about email and need a fake score to demo.

Why only ~40 rules? Isn’t that… thin?

On purpose. A wall of 400 undated “best practices” is how you look busy and still get burned. Every page needs a primary source we actually read. Thin and checkable beats fat and folklore. Europe, bulk inbox rules, measurement honesty, and protocol topics like BIMI/DMARC policy are on the shelf when we can cite them — not every Member State and not every vendor myth. Coverage map lists what we still refuse to invent.

Is this legal advice?

No. If it were, you’d have a billable hour and a longer PDF. This is a dated operator reference written by an email geek. Confirm anything high-stakes with counsel who knows your facts. Same for “will this make me compliant?” — no tool does that. Lawyers and judges do. We say what the sources say and what to do first on Monday.

Why no trust score out of 100?

Because we refuse to invent a number you can’t audit. Fake scores sell seed tests and panic. You get findings, dates, and links. If that feels less exciting than a red dial, good — you’re not the red-dial customer.

Why should I trust you more than my ESP’s blog?

ESPs sell seats. Seed-score vendors sell fear. AI invents citations when nobody watches. We sell nothing today — no pixels, no placement scores, no affiliate — so we can say when a tool is the problem. A human verifies, dates, and corrects in public. Tools may help draft; they do not ship unsourced claims. Check the primary links. Fail that test and leave.

Do I need an account?

No. Filters live in this browser and the URL. Share the link. That’s it. Accounts come later only if they earn it — not so we can nurture you about email.

I’m an agency. Where’s multi-client mode?

We tried a client-name CRM on the setup card. It made the product feel like work before it felt useful. Role filters + copy link + one-page brief (optional PDF title) is enough for now. Complexity comes back when the free shelf is habit, not before.

Is the quiet changelog a bug?

No. Quiet means nothing material moved. We don’t invent urgency so the homepage looks “alive.” Sticky risks still show what usually needs a person when the market is still.