Many wireless providers in the U.S. require customers to sign a two-year service agreement when purchasing a new smartphone, though some still allow subscribers to upgrade to a new device with a full subsidy once every 20 months. This may soon become a thing of the past, however. Verizon (VZ) on Friday announced that it will no longer be offering early upgrades to its customers. The carrier will allow subscribers who are set to receive an upgrade prior to September 1st, meaning their contract was going to expire on or before January 1st, 2014, to upgrade early. Customers who won’t be eligible for an upgrade until after September 1st will have to wait until the end of their 24-month agreements to buy a new smartphone, unless they wish to do so at full retail price. Verizon has also announced that it will remove all unused credits from its retired New Every 2 program on April 15th.