EU competition czar Margrethe Vestager has warned that Apple must treat all app developers fairly, as the company steps up its privacy protections and changes the way user data is handled.

Apple has said that new rules for tracking users outside a company's own apps and websites will take effect early this spring, following an initial postponement. The rules do not prohibit tracking, but they do demand that apps seek permission, allowing users to decide for themselves whether they want to be tracked or not. The changes will take effect as of iOS 14.5.

The change has been met with sharp criticism, mainly from companies such as Facebook, whose business model benefits from the use of tracking to target advertising. The social media giant has claimed the change is anticompetitive, and that Apple will exclude its own advertising platform from the rule.

Vestager - who is named on the European Commission website as "Executive Vice-President for A Europe Fit for the Digital Age and Competition" - has taken an interest in the latter point, Reuters reports. Even if the rules are designed to protect users, she comments, the situation could develop into an antitrust issue if Apple doesn't treat its own apps in the same way.

Apple itself has not commented on this development, but the company has previously said that the upcoming change will apply to Apple itself, and that its advertising platform will not track users.

This article originally appeared on Macworld Sweden. Translation by David Price.