It’s going to get harder for Android apps to track users who’ve opted out of receiving personalized ads, the Financial Times reports, after Google announced changes to how it’ll handle the unique device identifiers that allow marketers to track them between apps. From a report: Starting later this year, Google is cutting off access to these “Advertising IDs” after a user opts out, and will show developers a “string of zeros” in its place. The news was announced in an email to Play Store developers, and Google has also updated its support page for Advertising IDs with the announcement. Google told developers the changes will “provide users with more control over their data, and help bolster security and privacy,” the Financial Times reports. The change comes a few short months after Apple overhauled how advertising IDs work on iOS in an apparent attempt to compete with the new policy.