iOS 27 and email: what marketers need to know

Every September, Apple drops something that sends email teams scrambling for a test device. This year it's a bigger shake-up than usual. iOS 27 landed on 14 September, the foldable iPhone Duo goes on sale on 23 October, and Siri can now dig through your customers' inboxes for them.

That's a lot of news right before the busiest sending season of the year. So we've done the digging for you: what's changed, what it means for how you design, code and write your emails, and what's worth doing before peak.

The short answer: build fluid layouts that work at any width, put key details in live text, write clear subject lines and judge success on what happens after the click. Here's why.

What's new in iOS 27 for email?

Three updates matter most for email marketers:

• The iPhone Duo. Apple's first foldable has a 5.4-inch outer screen and a 7.6-inch inner screen. iOS 27 adapts layouts as the phone folds and unfolds, and Split View lets people run two apps side by side.
• Siri AI. The new Siri can search Mail, find specific messages and pull out details like confirmation numbers to use elsewhere on the phone.
• A smarter Mail app. Search now ranks the most relevant results first. Suggested actions (adding an event to Calendar, getting directions in Maps, tracking a delivery in Wallet) have a new design and work with third-party apps. Smart Reply can match the user's own writing style, and new "Ask Siri" buttons appear throughout the app – including for clearing out mail from specific senders.

Before anyone rewrites their whole programme, a reality check. Siri AI needs an iPhone 15 Pro or later, launches in English only (UK English included), is rolling out gradually and won't be on iPhone or iPad in the EU at launch. The iPhone Duo starts at £1,999, so it'll be a small slice of your opens for a while.

So no need to panic. But the direction is clear, and the brands that adapt early will be ahead when these features go mainstream.

How to design emails for foldable iPhones

On a foldable, one person can read the same email at two very different sizes – sometimes within seconds. Add Split View and your email might be squeezed into a narrow column on a big screen.

The good news? Solid responsive habits already cover most of this. The emails most likely to break are the ones built for exactly two scenarios: a small phone and a desktop. Here's what we'd check:

• Go fluid, not fixed. Hybrid layouts with percentage widths and a sensible max-width handle in-between sizes far better than rigid fixed-width tables.
• Test the awkward middle. Two-column modules, product grids and side-by-side images tend to wobble at tablet-like widths. Make sure they stack or scale gracefully, not just at your usual mobile breakpoint.
• Let images scale. Use max-width: 100% and height: auto so images fit whatever space they're given, and export them at twice their display size so they stay sharp on the larger screen.
• Watch your hidden content. If you show or hide elements with media queries, check nothing important disappears at a width you didn't plan for. Our guide to hiding elements in email covers the techniques.
• Keep tap targets generous. Buttons that feel fine on a small phone can get fiddly in a narrow Split View column.

How Siri AI affects email search

When customers can ask Siri to "find the email about my delivery", your email needs to be easy for a machine to find and understand, not just a person. That rewards clarity over cleverness:

• Keep your sender name consistent. If people search by sender, a name that changes from campaign to campaign makes you harder to find.
• Write subject lines that say what's inside. Playful subject lines still have their place in promotional sends. But for anything people will want to find again, like orders, bookings, tickets and account updates, specific wins.
• Put key details in live text. Order numbers, dates, times and addresses locked inside images are invisible to search and to Siri. Live text is better for accessibility too, so it's a double win.
• Remember the bulk delete. Siri can now help people clear out mail from specific senders. If your emails feel like clutter, that just got easier. Relevance and sensible frequency matter more than ever.

Why transactional emails matter more now

Suggested actions and Siri's ability to pull details from Mail make one type of email more valuable overnight: the transactional message. Confirmations, delivery updates and booking details are exactly what Apple Intelligence is designed to read and act on.

Transactional emails are often a brand's most-opened messages, yet they're usually the most neglected. Now's the moment to give them some love: clean structure, clear hierarchy, consistent formatting for key details and a look and feel that matches the rest of your CRM programme. If a customer's phone is going to turn your email into a calendar event or a delivery tracker, the details need to be spot on.

Will iOS 27 affect your email metrics?

Probably, yes. Since Apple's Mail Privacy Protection arrived, open rates have been unreliable for Apple Mail users. iOS 27 could start to muddy clicks too.

If Siri grabs a booking reference, or a suggested action adds an event to the calendar, some useful interactions will never show up as a click. The clicks you do get may come from people who are keener to act, but your click-through rate could still dip without anything going wrong.

That makes it even more important to measure what happens after the email: conversions, revenue, journey completion and fewer customer service contacts. If your reporting still leans on opens and clicks, now's a good time to rethink which numbers you watch.

Your iOS 27 email checklist

Run through these before your biggest sends of the year:

• Test your core templates at in-between widths, not just mobile and desktop.
• Check two-column modules and product grids stack or scale cleanly.
• Make sure images scale fluidly and stay sharp on larger screens.
• Move key details (order numbers, dates, addresses) out of images and into live text.
• Keep sender names consistent across campaigns.
• Make transactional subject lines specific and easy to search.
• Audit your transactional emails for structure and brand consistency.
• Agree which post-click metrics you'll use to judge peak performance.

None of this is wasted effort, even if your audience is slow to pick up foldables or Siri AI. Fluid layouts, clear copy and live text make every email better, wherever it's opened.

Fancy a second pair of eyes on your templates before peak season approaches? Get in touch with the team – we'd love to help.