How do I upgrade my phone T-Mobile?

upgrade on My T-Mobile or visit a T-Mobile retail store:

T-Mobile users may check whether they are eligible for an upgrade by signing into their My T-Mobile account and selecting “Upgrade Phone” . The carrier may allow you to buy a discounted phone as early as 12 months after your last upgrade, but only as long as you meet its conditions.22 Kas 2012

Once you have Jump, you can swap your phone for an upgrade whenever you want and T-Mobile will cover up to 50% of your original phone’s retail price . That means you’ll want to upgrade every 12 months to take advantage of Jump and justify that extra monthly fee.