When will Apple pay the bills for this huge iPhone upgrade?

By the end of this year, Apple will likely have enough cash on hand to buy back its existing iPhone, AppleInsider has learned.

We understand that the majority of the remaining iPhone owners will be upgrading to an iPhone XS, which will allow them to upgrade to a higher-end model, but the majority will be getting the iPhone X. AppleInsiders source AppleInsistently source Tech Insider