Diving deeper into iOS 26: What it means for SMS, MMS, and RCS

It's that time of year again. Every fall, Apple makes updates to its flagship iOS mobile operating system, opening up new opportunities for engagement and sending brands scrambling to make sure they're ready to take advantage. This summer, Apple unveiled its key announcements for iOS 26, including AI-summarized email inbox and a new Liquid Glass interface. Check out a breakdown of those changes and more in our blog post from June.

One of the updates Apple announced is set to have a significant impact on mobile marketers: SMS, MMS, and RCS messages from unknown senders will be filtered into a less visible "Unknown Senders" inbox within Messages. This makes it crucial for brands to take proactive steps to ensure their messages land in the main Messages inbox. Read on to learn more about this change, what it means for your brand, and how to address it.

Enhanced Message Filtering for SMS, MMS, and RCS

In the Messages app on Apple devices, users will now be able to screen SMS, MMS, and RCS from unknown senders, giving them more control over which conversations appear in their main inbox. Messages from unknown senders will appear in a dedicated Unknown Senders folder, where users can then "Mark as Known" or delete the message.Why this update matters for marketers

This change has significant implications for marketing messaging. For your SMS/RCS subscribers who enable this feature, your phone number or RCS verified sender will likely be considered an unknown number once this change goes into effect, making your messages much less visible and potentially resulting in dips in engagement. Spam reporting is also now easier for users, making it critical to send relevant and personalized messages that your customers value. Read on to learn more about how to respond to these changes.

Key Details:

• Unknown Sender filtering will be OFF by default: This is good news for marketers and will likely lessen the impact of this update. However, once this setting is enabled, it moves messages from unknown numbers into an “Unknown Senders” folder. The folder gets a small blue badge on the "Filters" icon within the Messages app when new messages arrive, but users receive no notifications, unless otherwise customized.
• Users can customize notifications for unknown messages: Within the “Unknown Senders” settings, users can choose to have the system notify them for certain types of messages from unknown numbers, including:
  • Personal: Identified as not sent by businesses or organizations
  • Transactions: Including order updates, receipts, and confirmations
  • Promotions: Including general offers and updates sent to multiple recipients
• Time-sensitive messages will still appear in the main inbox: Using on-device models, the system will identify time-sensitive messages, like verification codes and order confirmations, and surface them in the main conversation list for one hour, even if they are from unknown numbers.
• Existing subscribers who have interacted with your brand are grandfathered in: If a user has sent your brand a message via SMS/RCS—for example, sending a message as part of your opt-in flow, replying “Y” for double opt-in, or sending in a keyword for a promo—they will remain in the main conversation inbox, even if they haven't saved you as a contact or "Marked as Known."
• RCS for Business messages will not bypass this filtering: While the RCS verified sender offers enhanced brand recognition, this new channel is not immune to the update. However, customers may be more likely to open your message, "Mark as Known," or save your brand as a contact if they recognize your brand name and logo within the message thread.
• Suspected spam will automatically be routed into a Spam folder: This filter will be ON by default and based on regularly updated, user-input-driven, on-device protections designed to target phishing attempts. These messages will not receive notifications and will automatically be deleted after 90 days.

iOS 26 updates: What brands should do to respond

The good news? There are a couple ways to break out of the “Unknown Senders” folder and into the main Messages inbox.

1. Prompt users to "Mark as Known." When users open a message thread in the “Unknown Senders” inbox, they have two options: "Mark as Known" or "Delete." If they “Mark as Known,” it will move your messages to the main inbox. The system retains this "known" status even if the conversation is later deleted, so you're set for the future. Recommend “Mark as Known” early to new customers in your welcome or onboarding flows on other channels, or work it into your SMS/RCS opt-in flows for new subscribers. For example, after a customer subscribes, you might say, “Thanks for subscribing! Check your Unknown Senders folder and select 'Mark as Known' to receive important updates and promos from our brand.”

If your messages are already seeing lower engagement, consider sending a dedicated communication about this update on another channel—like email, push, web, or in-app messages—to encourage this behavior, especially for your engaged subscribers who you know value your messages!

2. Prompt users to save you as a contact. If you have MMS, you can send a Contact Card, which makes it easy for users to save your brand as a contact. If you don’t have MMS, you can simply encourage users to save your number as they would a friend.

For tips 1 and 2, consider segmenting your communications. This update affects users differently, and not everyone will need educational communications about it.

• For new SMS/RCS subscribers: Proactively educate users to "Mark as Known" or save you as a contact. Consider working this into your opt-in flows to maximize the impact of these efforts.
• For existing SMS/RCS subscribers who have never interacted with your brand: Proactively educate users on other channels, like email, push, in-app messaging, or web.
• For existing SMS/RCS subscribers who have interacted with your brand: You can have a high degree of confidence that these users will continue to receive your messages in their main inbox. There is likely no need to send educational communications to this group.

There are also some additional tips and tracks to be aware of to put your best foot forward:

• Don’t be spammy. iOS 26 makes it easier for users to report your messages as spam, so remember the guiding principles of good customer engagement: Sending the right message, at the right time, and on the right channel. Be sure to keep your messaging personalized, targeted, and always comply with mobile messaging regulations, including local laws.
• Consider multichannel reinforcement. For high-value communications, consider pairing your SMS/RCS with email or push. For example, use an email for important transactional alerts that won’t be considered Time Sensitive notifications, like changes to your company policy or account updates.
• Keep your promotional and transactional messaging on separate numbers. This is already a best practice to minimize unsubscribes that keep you from sending transactional messages, but it also increases the likelihood that transactional traffic (like OTPs) is surfaced as Time Sensitive since it’s isolated from marketing messages.
• Use clear one-time password (OTP)/transactional formats. Apple prioritizes the recognition of one-time passcodes and urgent alerts for Time Sensitive delivery. Using clear, simple formats will help ensure delivery.

Final thoughts

With the release of iOS 26, mobile marketers may see temporary dips in mobile messaging visibility and engagement. But this update, while serious, is far from insurmountable. By implementing the recommendations we’ve provided—from prompting users to "Mark as Known" to refining your messaging strategy—you can help your messages continue to be seen and valued by your customers.