On a regular basis I check my upgrade eligibility at AT&T Wireless.  For the last 16 months that date has been September 30, 2011.  As noted below from a screen shot I took a few months back.

Yesterday upon checking the date of eligibility the date changed to 9/29/11. For those tracking at home this is the last Thursday in September. Here is that screen shot.

Apple stated in its earnings call that a “new product that [it] [couldn't] discuss” would lower gross margins in September, iOS 5 is due in the fall and well there wasn’t a new iPhone in June like each year since 2008. On that exact day of the earnings call I discover my upgrade date rolls back a day. Or it could just be the system correcting what 18 months in AT&T’s world actually means.