When you close an app on your iPhone, iOS stops it from running in the background. Even so, Apple implemented a feature back in iOS 10 that wakes apps up to customize and deliver notifications. While the feature leads to better notifications, some apps take advantage of the feature by sending analytics and other data during the notification process.
YouTube channel Mysk recently posted a thorough video overview of the apps, covering well-known software from companies like X/Twitter, Facebook, LinkedIn, and TikTok. Some of the apps send data upon waking, while others send a ton of unexpected data when the user clears the notification.
The information being sent isn’t all benign, either. The apps send unique data about the user’s device that could enable tracking across apps. Some of the transmitted data includes system uptime, the device name and type, and more. Mysk’s demonstration showed a shocking number of transmissions from LinkedIn, which sprung to life when the user cleared the notification to send several pieces of data.
While annoying and potentially invasive, there are ways around this practice without ditching third-party apps altogether. Some in the comments asked how to prevent this from happening and got a simple response: Turning app notifications off should do the trick, but you’ll have to toggle the option for each app to disable them.
That “fingerprinting” technique gives the app developers far more information than the user realizes, but Apple is thankfully making changes to its policies to block the practice. The company will require developers to detail the need for APIs and disclose those that send data for fingerprinting.