Apple is ought to announce the upcoming iPhone event later this month, the event traditionally takes place in September. A likely date is September 7, as earlier rumors pointed to a pre-order kick-off on September 9. The actual in-store sales will begin on September 16. However, carriers have a slightly different roadmap. A newly leaked AT&T retail schedule details merchandising reset hours and the two dates listed are September 9 and September 23. That' a week later than previously expected. Apple's 2015 iPhone event invitation 9to5Mac speculates that both September 16 and...
Source: http://www.gsmarena.com/iphone_7_and_iphone_7_plus_to_start_selling_at_carriers_as_late_as_september_23-news-19999.php