Trade iPhone 4 for iPhone 5s TMOBILE?

Hey guys well I got my iPhone 4 I guess last October and every time I ask him for a new phone he says he's still paying for my phone but I'm wondering if having JUMP from TMOBILE matters to trade in iphones where after 6 months you can get any phone you want does it matter? Please help Can I trade in my iPhone 4 tomorrow for an iPhone 5s?

If you are on the JUMP program and IF you have paid 50% of the price of the phone, you can trade up, but you will need to make sure that there's nothing wrong with the phone you are trading, no cracked screen or back, MUST power on be in working condition.