NEW YORK (AP) — T-Mobile is allowing people who participate in its $10-a-month Jump program to upgrade their phones anytime, eliminating the previous limit of two upgrades a year.As introduced last summer, Jump participants get insurance to cover loss and damage, plus the right to upgrade before fully paying off the phone in installments over two years. The customer must turn in the old phone. There was a six-month waiting period before the first upgrade and a limit of two upgrades per year.Starting Sunday, the waiting period and the upgrade limit are both eliminated.The catch is that customers must have paid at least half of the phone’s costs before turning it in.