Your preheader has been replaced by a summary

by Francis Rozange | Sep 8, 2026 | Email Marketing

Abstract 3D render: a paragraph-shaped block of light folded into one dense luminous line

You spent time on your preheader. That line of text following the subject in the message list, which guides present as the second subject line, and on which part of your open rate depends.

On an iPhone with Apple Intelligence, that line no longer exists. It has been replaced by a machine-generated summary, and Apple documents it in plain words.

The setting that says it all

It is called “Summarize Message Previews”, and Apple’s help page describes its effect without hedging:

“When you turn on Apple Intelligence, summaries automatically appear under your emails. You can turn off summaries if you want to see the first lines of the most recent message instead.”

The first lines of the message, meaning your preheader, only appear if the user turns the feature off. By default, they are replaced.

Apple announced this back in June 2024, in the language of user benefit: “instead of previewing the first few lines of each email, they can see summaries without needing to open a message”.

Two concordant sources, eight months apart, same conclusion. The preheader is no longer read by the recipient: it is read by a model, which renders back what it chooses.

Note too that the same feature sorts: “Priority Messages to quickly view your most urgent emails, like a same-day dinner invitation or boarding pass.” A section at the top of the inbox, where your campaign will not be.

At Google, the same thing, with one exception

Google started with summaries on mobile, in May 2025: “summaries will be available at the top of the email content for messages where a summary is helpful, such as longer email threads or messages with several replies”.

Then in January 2026, the general rollout, announced on the official blog: “When you open an email with dozens of replies, Gmail synthesizes the entire conversation into a concise summary of key points. […] AI Overview conversation summaries are rolling out today for everyone at no cost.”

United States first, English first.

And this is where the only good news in this article arrives, provided you are in Europe.

The line English-language coverage never quotes

Gemini summaries depend on a setting called “smart features”. The corresponding help page contains this box:

“Important: By default, smart feature settings are off if you live in: The European Economic Area, Japan, Switzerland, United Kingdom.”

In Europe, Gmail’s smart features are off by default. So the summaries are too.

That is the exact opposite of the situation described in almost every article on the subject, written from the United States, where the setting ships enabled.

Practical consequence for a European advertiser writing to European recipients: the preheader still counts at Gmail, and it already does not count at Apple, whose setting is not geographically scoped.

One campaign, two regimes, depending on the recipient’s phone.

What nobody documents

Then comes the question everyone asks: how do you write to be summarised well?

We do not know, and nobody knows, because neither vendor publishes anything about how its summaries treat the content of a marketing email.

Google documents nowhere the fate of the preheader, hidden text, display:none content or alt attributes in the generation of a summary. The only adjacent page deals with malicious content and prompt injection, not legitimate hidden text.

Apple publishes no more about the logic of its summaries.

That documentation vacuum will produce, in the coming months, an abundant literature of recommendations. Remember that none of it will rest on a primary source, and recall what unsourced figures and rules are worth in this trade.

The markup that exists, and is not that

A confusion is already setting in, and it is better dispelled now.

Google does publish two email markup mechanisms: schema.org markup, and Promotions tab annotations. Both are documented, active, and updated as of 22 July 2026.

Annotations drive display in the Promotions tab: product carousel, single image, discount code, validity dates. The schema.org markup feeds actions and highlights in the interface.

No Google documentation establishes a link between those tags and summary generation. Claiming that markup improves your summary would be an extrapolation, and we will not make one.

They are two distinct subjects, one documented, the other not.

What it really changes

A summary happens after the message arrives. It therefore changes nothing about whether your messages arrive, which remains settled by authentication, reputation and complaint rate.

What it changes is the value of artifice. A preheader promising what the message does not contain, a hook built to intrigue without informing, hidden text meant to steer a display: all of that is written for a human skimming. A model that summarises reads everything, and renders the substance.

Techniques resting on the gap between what you show and what you say lose their support. That is not a revolution, it is a narrowing of the playing field.

What to do tomorrow morning

Do not rewrite your preheaders to please a model. You have no documentation on which to base a decision, and you may have some in six months.

Instead run the test that costs five minutes: send yourself your next campaign on a recent iPhone with Apple Intelligence enabled, and look at what the summary keeps. If that summary makes your message boring, your message is probably boring and the preheader was compensating.

Then check the structure of the message rather than its hook. A clear proposition in the opening lines of the body, a single expected action, content that stands without artifice: those are the same qualities that survive the summary, the text-only view and image blocking.

And keep the geography in mind. Your European recipients on Gmail still see your preheader. Those on iPhone do not. Neither population can be guessed from your database.

Sources

LaFactory works email on the evidence: headers, DNS records, rejection logs. No open rate promises, ever. Get in touch for a deliverability audit.