Twitter’s impending relaunch of its subscription product, Twitter Blue, could bring Elon Musk’s fight with Apple to a head.

Twitter Blue Verified, as the product is called, had been scheduled to roll out on Friday but only on Apple’s iOS mobile software, according to a person briefed on the plans. (Late Tuesday, Twitter postponed the planned launch without setting a new date, according to a person briefed on the plans.) And because Twitter plans to launch the subscription offering via an update to Twitter’s iOS app, according to internal documents from earlier this month viewed by The Information, it needs Apple’s approval as part of the standard app review process. Twitter will update its Android app later, although the time frame couldn’t be learned.