AT&T didn’t think Mondays sucked enough, so today they enacted a policy change. Previously you were allowed to upgrade your device every 20 months at full discount. Starting on any contract ending after March 2014 you will have to wait the full 24 months to take advantage of an upgrade.
Verizon has already switched to the 24 month cycle leaving Sprint as the only major U.S. carrier still operating on a 20 month cycle for upgrades. T-Mobile has completely done away with contracts.
Enjoy you four extra months of outdated device ownership next year.