Apple’s Privacy Evolution: From ATT to ULS
Apple’s path toward a privacy-first digital ecosystem has been years in the making. Each step has introduced new challenges for advertisers and analytics platforms:
iOS 14.5: App Tracking Transparency (ATT)
The App Tracking Transparency (ATT) framework was the first major blow to traditional tracking. It forced apps to request permission before collecting user-level data and sharing it across apps and websites.
The result? Opt-in rates were low, limiting the effectiveness of deterministic tracking methods like IDFA (Identifier for Advertisers). Platforms like Meta and Google pivoted quickly, investing heavily in aggregated data, modeled conversions, and privacy preserving technologies.
iOS 17: Link Tracking Protection (LTP)
Apple’s next move came in iOS 17, which introduced Link Tracking Protection (LTP). This update automatically removed common tracking parameters (e.g., gclid, fbclid, msclkid) from links shared in Messages, Mail, and Safari’s Private Browsing mode.
While LTP didn’t completely break attribution, it signaled Apple’s intent: to strip away passive tracking methods and put more control in the hands of users.
iOS 26: Universal Link Sanitisation (ULS)
Enter iOS 26 and its most ambitious privacy update yet: Universal Link Sanitisation (ULS). Unlike LTP, which was limited to private browsing or Apple native apps, ULS applies across all browsers and all in-app web views.
That means tracking parameters are now stripped at scale, making it far more difficult for marketers to follow a user from click to conversion.For the first time, attribution is disrupted across all channels and contexts.
Why iOS 26 Matters More Than Previous Updates
The difference between ULS and previous privacy features is scope. ATT limited data sharing between apps. LTP reduced tracking in certain contexts. But ULS affects all browsers and apps, making it a significant shift.
For marketers, the impact includes:
- Loss of deterministic attribution: Campaign parameters like gclid and fbclid are the backbone of platforms like Google Ads, Facebook Ads, and Google Analytics. With these stripped, click-through attribution becomes unreliable.
- Increased reliance on modeled conversions: Platforms will fill in the gaps using machine learning models. These are useful but not 100% precise.
- Fragmented customer journeys: The seamless flow of data across channels and devices is broken. Understanding how different touch points influence conversions will require new methodologies.
- Reduced visibility in Google Analytics: UTM parameters and auto tagging mechanisms are compromised, making it harder to track campaign level performance with confidence.
In other words: ULS doesn’t just make measurement harder. It forces marketers to rethink how they prove value, allocate budgets, and communicate results to stakeholders.
What This Means for Brands
For many hospitality groups, these changes present a unique challenge. Many of the most effective digital campaigns in hospitality rely on paid search, paid social, and email acquisition channels that have historically leaned heavily on URL parameters for attribution.
Under iOS 26, the connection between a Facebook ad promoting a new seasonal menu and a customer actually booking a table or signing up to a mailing list is harder to trace. The same goes for Google Ads campaigns driving traffic to event pages or “Book Now” CTAs on pub websites.
This doesn’t mean those campaigns are less effective. It means the reporting visibility is reduced. Without adjustments, pubs and hospitality operators risk underestimating the value of digital campaigns that are still filling seats, selling pints, and driving repeat visits.
Google’s Response and Its Limits
It’s worth noting that Google has long been preparing for this world. After ATT disrupted tracking, Google leaned on two strategies:
- Tracking Parameters: Using identifiers like gclid (Google Ads) and fbclid (Meta Ads) to capture campaign data.
- Conversion Modeling: Filling in the blanks where deterministic data is missing by estimating conversions through machine learning and aggregated insights.
But ULS directly undercuts the first strategy by stripping parameters at the source. That leaves Google and other platforms with only one option: modeling.
While modeling has become increasingly sophisticated, it is still probabilistic. It can give a strong directional sense of performance, but it cannot offer the precision marketers once expected.
What This Means for Google Analytics
For many hospitality brands, Google Analytics (GA4) has been the single source of truth for campaign reporting. But under iOS 26:
- Session data may be incomplete if UTM parameters are stripped.
- Attribution reports will skew as campaign information is lost.
- Cross-channel comparisons will be harder to trust since referral information is blurred.
The end result is a more opaque measurement environment. GA4 can still provide value, but it will need to be supplemented with other techniques to paint a more accurate picture.
How Hospitality Marketers Can Adapt
So, what should Brands be doing now that deterministic tracking is no longer reliable? At Propeller, we recommend:
- Prioritise Authentication
Encourage guests to log in or sign up when booking tables, buying gift vouchers, or joining loyalty schemes. Authentication allows operators to stitch together customer journeys without relying on stripped URL parameters.
- Strengthen First Party Data Strategies
Hospitality operators are well positioned here. Reservation systems, Wi-Fi sign ups, and loyalty clubs already generate valuable first-party data. Consolidating these touch points into a unified CRM will be critical for measuring and activating campaigns.
- Rethink Measurement Frameworks
Traditional last click attribution isn’t fit for purpose. Hospitality operators should work with agencies to explore:
- Media Mix Modeling (MMM) to understand channel impact.
- Incrementally Testing to prove causal lift from campaigns.
- Customer Lifetime Value (CLV) models to measure not just bookings, but long term repeat visits.
- Embrace Modeled Data (With Caveats)
Modeled conversions from Google and Meta will be part of the toolkit. The key is to manage expectations: accuracy won’t be perfect, but when combined with first party data, modeled insights are still actionable.
- Educate Stakeholders
Operators must understand that a lack of precise attribution doesn’t mean digital campaigns are underperforming. At Propeller, we help translate modeled data into business outcomes that matter in hospitality, like covers booked, dwell time increased, events sold out, or incremental spend per guest.
Turning Disruption Into Opportunity
It’s easy to view iOS 26 as a setback. But there’s a more optimistic perspective: this is a chance for brands to future proof how they measure success. By focusing less on pixel perfect attribution and more on direct customer relationships, loyalty, and long term value, brands can actually come out stronger.
Final Thoughts
The arrival of Universal Link Sanitisation is not the end of attribution, but it is the end of doing things the old way. Deterministic tracking through parameters like gclid and fbclid is gone. What replaces it is a more resilient, privacy safe approach built on:
- Encouraging authentication at key booking and loyalty touch points.
- Building first-party data ecosystems from reservations, Wi-Fi, and loyalty clubs.
- Using modeled conversions and advanced measurement (MMM, incrementally testing, CLV).
For hospitality operators, this shift is an opportunity to better connect marketing activity with real world outcomes: covers booked, pints poured, and guests returning more often.
For Propeller, it’s a chance to partner even more closely with our clients aligning on measurement frameworks, designing campaigns that thrive in this new privacy first environment, and ensuring marketing investment translates directly into business growth.
We believe agencies and business operators must work together more closely than ever. By combining Propeller’s expertise in digital media and measurement with the on the ground customer knowledge of our clients, we can turn iOS 26 from a challenge into an opportunity to build stronger, more sustainable growth strategies.
If you’re ready to adapt your measurement framework and keep hospitality marketing thriving in a privacy first world, get in touch with our team today.