Unknown sender engagement is down 30-40%, and with iOS 26 making filters smarter than ever, getting into your customers' main inbox has never been more important.

Updated with the latest iOS 26 information as of November 12th, 2025.

The information in this article is based on extensive internal Attentive research data. As Apple continues to release iterations of their iOS 26 mobile operating system, we expect the behavior to evolve. Before taking any direct action in order to mitigate iOS 26 impact, please consult with your Attentive contact(s).

Every September, Apple’s annual iOS release sparks a wave of excitement (and a little anxiety) for brands that rely on mobile messaging to connect with their audience. This year was no different. With iOS 26, Apple is introducing changes to how text messages are displayed in the Messages app, and it has created buzz among marketers.

The key update with iOS 26 is a change to Apple’s ‘Screen Unknown Senders’ setting. The new inbox organization and filtering tied to the setting can determine whether your brand’s messages appear front-and-center in a user’s inbox, or if your message gets quietly tucked away in the “Unknown Sender” inbox, where it may never be seen.

At Attentive, we’ve been running thousands of tests for each beta version of iOS 26 (released in September). We wanted to highlight the changes, their significance, and how Attentive customers are already well-prepared to adapt.

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Key Takeaways

• iOS 26 expands on “Screen Unknown Sender” functionality: In iOS 26 (launched in September), Apple’s “Screen Unknown Sender” setting filters messages from “Unknown Senders” out of the main inbox into a separate inbox, without triggering notifications. The setting is defaulted off, but we’ve seen through extensive research that roughly 55%+ of Apple phones have it enabled.
• iOS 26 “Screen Unknown Sender” functionality has a significant impact on text performance: While only ~23% of consumers have updated their iPhones to iOS 26, we expect 70%+ to have it installed by the end of the year. For messages that land in the Unknown Sender inbox, we’ve seen clickthrough rate and conversion rate drop by 30-40%, and text marketing program revenue drop in parallel.
• Attentive keeps your messages front and center: Attentive’s patented two-tap™ technology is the only sign-up method classifying senders as “Known Senders,” delivering all messages to the Main Inbox. This includes new subscriptions (opted-in after users updated to iOS 26), as well as existing subscriptions (current lists).
  
  • All other sign-up flows will be impacted
  • While the majority of sign-ups Attentive brands have collected are two-tap™, our new suite of iOS 26 tools and strategies will help minimize the impact for affected brands

Attentive continues to shape the future of mobile messaging: As a CTIA board member with deep relationships with carriers, Attentive is recognized for focusing on compliance and eliminating unwanted messages. We have been planning for the future of the messaging inbox for years, and have continued innovating with AI personalization to maintain placement in the Main Inbox.

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What is the “Screen Unknown Senders” setting? Why is it important?

Apple's "Screen Unknown Senders" is designed to filter messages from "Unknown Senders" out of the Main Inbox into a separate "Unknown Senders" inbox. This setting is off by default, but from our research, we've seen that users have this filter enabled 55%+ of the time on iOS 18 and in iOS 26. The status of this setting is copied over after upgrading from iOS 18 to iOS 26.

Following the iOS 26 release, nearly half of shoppers (48%) are now filtering messages from unknown numbers, with adoption rates climbing even higher among younger users—63% for Gen Z and 60% for Millennials. In addition, over a third (39%) rarely review their filtered inbox, with Gen Z users nearly half (48%) neglecting to check it. 

With iOS 26, Apple has significantly changed how this filter works. When the setting is turned on, two distinct inboxes appear in the messages app:

• Main Messages inbox: This is the default inbox where messages from trusted senders appear. There is no change to those messages versus the experience today. 
• Unknown Senders inbox: This is a secondary inbox hidden within the menu in the top right of the Messages application. Crucially, messages routed here do not trigger notifications or message previews. As a result, even opted-in subscribers may miss your message entirely if it lands in this inbox.

While a version of this filter exists on iOS 18, it was far less disruptive—messages from unknown senders appeared in the default "all messages" tab alongside messages from Known Senders. In iOS 26, that safety net is gone when a user activates the setting—if you’re filtered, you’re filtered.

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How does iOS 26 determine Known vs. Unknown?

Based on our extensive testing, iOS 26 classifies a phone number as “Known” if:  

• The phone number is saved as a contact
• The user clicks on “Mark as Known”: Once iOS 26 rolls out, Unknown Sender message threads will include a button that users can click on to permanently mark the sender as Known, moving the thread to the Main Inbox
• The user initiated the conversation: This marks the phone number as “Known” permanently 
• The conversation includes 3+ messages from the user. While iOS 26 documentation provides this guideline, we have not seen this replicated in testing.

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Not all sign-up flows are treated equally in iOS 26

Based on thousands of tests across every iOS 26 beta, Attentive’s patented solution is the only sign-up method that provides a frictionless sign-up experience and marks senders as “Known”, permanently delivering all messages to the Main Inbox in iOS 26. The “Unknown Senders” filter impacts both new subscriptions that will occur after users upgrade to iOS 26, as well as existing subscriptions (your current list). Here’s how messages to subscribers sourced through the most common sign-up methods behave in the latest version of iOS 26:

• Two-tap™ sign-up units: No impact. two-tap™ sign-up units require the subscriber to send the first message. This classifies the brand as a “Known Sender” from day one, consistently delivering all messages to the Main inbox with full notifications. This also applies to messages to subscribers who opted in with two-tap™ before upgrading to iOS 26. 
• ‍Reply-Y sign-up units: Highest impact. This sign-up flow starts with brands sending the first message, asking users to confirm their opt-in to marketing programs by replying “Y.” As a result, Apple categorizes the sender as “Unknown,” and delivers all messages (sign-up flow and subsequent messages) to the Unknown Sender inbox.
• ‍On-site Opt-in (2FA) sign-ups: High impact. Similar to Reply-Y, this sign-up flow starts with a brand sending a text confirmation code that the user must re-enter on a site, classifying the sender as Unknown. The message containing the code may trigger Apple’s “time-sensitive” setting, which temporarily surfaces Unknown Sender messages with urgent content in the Main Inbox. However, all subsequent messages are filtered to the Unknown Sender inbox.

While iOS 26 introduces real challenges for certain sign-up methods, the good news is that Attentive customers already have built-in protection. Our patented technology and other user-initiated sign-up flows ensure your messages continue to land in the main inbox—exactly where subscribers expect to see them. 

Brands relying on other non-two-tap™ sign-up flows have seen a 30-40% impact on click-through rate and a 30-40% impact on conversion rate for messages that land in the Unknown Sender Inbox, directly impacting text marketing revenue.

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The temporary exception to the rules: Time-sensitive messages

Apple designed this safeguard to ensure that urgent messages (like two-factor authentication (2FA) codes) temporarily appear in the main inbox, even if they come from a number Apple classifies as “Unknown.” In these cases, the user receives the message with push and badge notifications. Once that short window closes, the message thread and any future messages from the same sender are only surfaced in the Unknown Sender inbox. 

“Time sensitive” is automatically enabled whenever a user turns on “Screen Unknown Senders”, but can be disabled by the user.

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How Attentive keeps your messages visible on iOS 26

There are a few ways Attentive is able to help you navigate these new developments:

• Two-tap™ advantage: Our patented two-tap™ technology sign-up units are the only sign-up method that provides a frictionless experience while enabling brands to deliver messages to subscribers’ main inboxes as intended. Because subscribers initiate the conversation when opting in, brands are automatically recognized as trusted senders. This not only safeguards deliverability in iOS 26 but also historically has driven stronger performance—two-tap™ consistently higher sign-ups compared to other industry methods.
• Messaging ecosystem leadership: Apple’s Unknown Sender filter was designed to protect users by reducing unwanted messages. As a CTIA board member with deep carrier relationships, Attentive has long been at the forefront of compliance, shaping standards that safeguard the channel while maintaining brand reach. Our leadership role has been critical in eliminating bad actors and enabling a more trusted, spam-free environment for both consumers and brands.
• Product innovation: Attentive’s ongoing product innovation ensures that brands stay ahead of the evolving messaging landscape. Beyond compliance and deliverability, we’ve invested heavily in AI-driven personalization that makes every message not just delivered, but timely and relevant. By combining channel leadership with advanced personalization, we help brands break through inbox clutter and deliver messaging that consumers value.

‍Notably, at Attentive we’re actively developing new tools to enable brands to continue to reach their subscribers even with iOS 26 filtering logic in place. Attentive customers benefit from access to our patented two-tap™ technology on mobile and beyond (available today in a Closed Beta on desktop), as well as new Inbox Visibility Tools to address subscriptions impacted. If you would like to learn more about our latest iOS 26 offerings, please schedule some time with our team.

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What can you do now?

iOS 26 officially released to users on September 15, 2025. Since the release, we’ve seen that approximately 23% of iOS users have upgraded to the latest operating system. Based on historical iOS adoption trends, we expect iOS 26 adoption to ramp to 70%+ by the end of the year.

Brands should focus on adjusting their strategy over the next two months to minimize impact on program performance during the holiday season:

• Migrate your sign-up units to Attentive: Our patented technology sign-up units start with direct user engagement, guaranteeing that your messages continue to be classified as ‘Known’ and are delivered to the main inbox. Moving your sign-up flows to Attentive ensures that you’re taking advantage of this built-in protection. This is the most powerful solution compatible with the iOS 26 inbox changes, and our patented technology is unique to the Attentive platform. 
• Incorporate Contact Cards into your Welcome Journeys: Including Contact Card as part of your Welcome Journey is a simple yet powerful way to boost deliverability. When a subscriber saves your brand as a contact, it will permanently establish your brand as a ‘known sender’ for that contact. This way, you can make sure that your messages continue to land in the main inbox with notifications.
• Engage new subscribers where possible: Early interactions with your brand can help secure the ‘known sender’ status. Apple specifies that brands engaging in conversations including 3+ subscriber responses will be classified as “Known,” however testing has shown varying results. We encourage brands to experiment with engaging subscribers in conversations, recognizing that the iOS logic may evolve. Attentive’s significant investment into conversational capabilities—from Concierge AI to customer conversational flows—to Welcome Journeys, and follow-up offers can all play a critical role in reinforcing that recognition.
• Provide clear guidance on non-two-tap™ sign-up units: Since "Reply Y" confirmation messages are now directed to the Unknown Sender inbox, we've noticed that giving specific instructions during the sign-up process can significantly reduce the impact on iOS 26. A great starting point is to include phrases like "Make sure to check your Unknown Sender inbox" on the sign-up units.

While iOS 26 is changing message inbox behavior and filtering, we expect it to continue to evolve in coming months/years. At Attentive, our team of deliverability experts are committed to bringing you the best messaging experiences. We will continue to work closely with our industry partners to shape the future of messaging, rigorously test new iOS releases, and evolve our product to stay ahead of the changing messaging landscape.

If you are a current customer and have any specific questions about the iOS 26 update, please get in touch with your Attentive contact. If you are not yet an Attentive customer, you can schedule some time to talk with the team. We’re more than happy to continue to work closely with you in order to ensure that you continue to have a top-performing text program.