Multiple sources have informed BGR that AT&T has blacked out vacation days for the second half of September in preparation for the iPhone 5S launch date. This has taken place every single year starting with the first iPhone launch, and it limits AT&T employee vacations and time off. We were also told that AT&T will not be launching any other high-profile devices during the second half of September, again confirming that this time period is for the upcoming iPhones. An earlier report noted that T-Mobile has issued a vacation blackout for September 20th through the 22nd, and coupled with an almost-confirmed September 10th announcement event, it sure looks like September 20th is a go for launch in the U.S. and other countries.

The iPhone 5S is reportedly physically similar to the iPhone 5, and has internal enhancement and upgrades such as a faster processor, more memory, a better camera and a fingerprint sensor. The iPhone 5C should use most of the iPhone 5 components, except it will repackage them in a plastic case that will be available in multiple bright colors and for a lower price than Apple’s current phones.

We have reached out to AT&T for comment but have not yet heard back.