FILE PHOTO: A customer tests a smartphone during the launch of the new iPhone XS and XS Max sales at "re:Store" Apple reseller shop in Moscow, Russia September 28, 2018. REUTERS/Tatyana Makeyeva/File Photo
Facebook faces up to a 7% decline in second quarter revenue if 80% of its users block the company from tracking them on iPhones. Reuters 

Why iPhone's privacy update might hit Facebook's Q2 revenue