T-Mobile is allowing participants of 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 , 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 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 's costs before turning it in. Typically, that means customers who have had the phones for less than a year would have additional payments to make right away.