rule changes. Head of ad products for Facebook Dan Levy commented, saying that "this is not really about privacy for them, this is about an attack on personalized ads and the consequences it's going to have on small-business owners," commenting on the full-page ads placed by Facebook in various newspapers in December 2020. Customer privacy Apple has a notable pro-privacy stance, actively making privacy-conscious features and settings part of its conferences, promotional campaigns, and public image. With its iOS 8 mobile operating system in 2014, the company started encrypting all contents of iOS devices through users' passcodes, making it impossible at the time for the company to provide customer data to law enforcement requests seeking such information. With the popularity rise of cloud storage solutions, Apple began a technique in 2016 to do deep learning scans for facial data in photos on the user's local device and encrypting the content before uploading it to Apple's iCloud storage system. It also introduced "differential privacy", a way to collect crowdsourced data from many users, while keeping individual users anonymous, in a system that Wired described as "trying to learn as much as possible about a group while learning as little as possible about any individual in it". Users are explicitly asked if they want to participate, and can actively opt-in or opt-out. With Apple's release of an update to iOS 14, Apple required all developers of iPhone, iPad, and iPod Touch applications to directly ask iPhone users permission to track them. The feature, titled "App Tracking Transparency", received heavy criticism from Facebook, whose primary business model revolves around the tracking of users' data and sharing such data with advertisers so users can see more relevant ads, a technique commonly known as targeted advertising. Despite Facebook's measures, including purchasing full-page newspaper advertisements protesting App Tracking Transparency, Apple released the update in mid-spring 2021. A study by Verizon subsidiary Flurry Analytics reported only 4% of iOS users in the United States and 12% worldwide have opted into tracking. However, Apple aids law enforcement in criminal investigations by providing iCloud backups of users' devices, and the company's commitment to privacy has been questioned by its efforts to promote biometric authentication technology in its newer iPhone models, which don't have the same level of constitutional privacy as a passcode in the United States. Prior to the release of iOS 15, Apple announced new efforts at combating