iOS 17: say goodbye to GCLIDs; embrace change!

It’s time to chat about the buzz surrounding Apple’s latest updates, iOS 17 and macOS Sonoma, and how they’re shaking up the world of online tracking.

iOS 17’s Link Tracking Protection is Apple’s response to the growing concern for user privacy. While it presents challenges, it also pushes advertisers to explore more privacy-friendly tracking methods and adapt to changes in the digital advertising world.

Your marketing campaigns in Google Ads, Meta and Bing are, as we speak, already negatively affected by this. So you need to undertake action now. In this series of two blog posts we will help you towards the solution.


So, rewind to 2017 when Apple introduced Intelligent Tracking Protection (ITP). It was like the superhero of the web, fighting off third-party cookies and putting a leash on certain first-party cookies. Then, in 2021, iOS 14.5 made app developers ask for permission before snooping on your advertising ID. Talk about putting a wrench in the data-collecting party, especially for the Facebook crew. Now, fast forward to 2023, and here comes iOS 17 and macOS Sonoma, ready to rock the boat once again. What’s their game plan, you ask? They’re here to change how Apple deals with URL tracking parameters.

The Problem

Alright, let’s break it down. LTP, aka Link Tracking Protection, is the name of the game. With iOS 17, it’s like Apple’s swiping the click IDs from marketers’ hands, at least for now, in certain situations, which I’m going to explain. We are talking about marketing URL parameters and they will be stripped from the URL in these three cases:
  1. On links shared from Messages and Mail

E.g.: Apple’s ‘share’ functionality to share a link that the user receives in Messages, and the link has a tracking parameter on it.

  1. On links encountered while browsing in Private Mode in Safari on iOS or MacOS (advanced tracking and fingerprinting protection feature):

E.g.: While browsing the web in Private Browser Mode the user lands on a sponsored page or a page with any clickID.

  1. The advanced tracking and fingerprinting protection isn’t restricted to Private Mode, because it’s possible to enable it for all browsing sessions. And once it’s enabled, it will impact all the links.

In all these cases, the click IDs are going to be stripped from the URL the second the browser is loaded. 



Not all parameters are going to be affected, at least for now. The ones that will be removed are: 

  • gclid (Google Ads), 
  • dclid (Google Display Network), 
  • fbclid (Facebook Advertising), 
  • twclid (X Advertising),
  • mscklid (Microsoft Advertising),
  • igshid (Instagram), 
  • mc_eid (Mailchimp email). 

On the other hand, custom parameters, general UTM parameters, and a few others are still working such as: 

  • UTM (utm_medium, utm_source, … ),
  • epik (Pinterest), 
  • _kx (Klaviyo), 
  • tt (TikTok), 
  • dm_i (dotdigital),
  • ir (Impact Radius),
  • Other custom parameters.

Impact Analysis

But why does it matter that these user-level parameters are vanishing into thin air? Well, iOS 17 is likely to be dropped in late September or early October of 2023, and for sure people will start adopting it. Slowly at first, but we’re talking about 90% of Apple users by the end of Q1 2024. That’s a massive crowd.

Here is some data to consider:

  1. iMessage has 9% of the market in the Netherlands [1];
  2. Safari is the second most popular browser worldwide [2]
  3. Apple’s email client has a market share of 58% in 2023 [3]

So when these changes hit, it’s going to shake up the marketing world. 

Why Marketing Data might be affected?

Why does all this matter for marketing data? Well, it’s all about cross-channel attribution and, letting advertisers see exactly how users moved from point A to B. But, without those user identifiers, they rely on probabilistic models. While that might not necessarily be a bad thing, advertisers will have to challenge the way they work. 

Using Enhanced signals is another important use case that would be heavily affected by the absence of user identifiers. With individual signals, advertisers are able to enrich their conversion tracking with additional parameters such as profit data, offline conversions, returns etc. Without individual identifiers, it will be a struggle to achieve this.

The First-party identifiers are also needed to be able to match users and retarget audiences. Without them, we are not able to flag an individual user as part of an audience based on their website behavior.


So, Apple’s iOS 17 and macOS Sonoma are shaking up the tracking game, and marketers will need to adapt because the rules are changing. There are a few solutions possible to implement and avoid losing all this tracking like Private Click Measurement (PCM), Intercepting HTTP Requests with a Proxy Server, Header Parameters and Masking Parameters.

Next week, we will dive into these solutions which will help you counter this step taken by Apple in today’s rat race. Stay tuned!

If you want to step up your game to counter the measures today, reach out to Wout Smelt or Suze Löbker today.

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