Upgrade to an iPhone 6S for free with this carrier

T-Mobile will be giving its customers the option to upgrade their iPhone 6 when the next iPhone model is released later this year at no extra cost.

With an iPhone 6S, iPhone 6C and even an iPhone 6S Plus expected to be released next, if you are already on T-Mobile's plan with an iPhone 6, the 'Uncarrier' will lock in the monthly repayment cost for the next iPhone model when it comes out later this year.

The upgrade will also be free as part of its new Jump OnDemand feature, so beyond the monthly $15 handset repayment, you won't be charged extra for the new handset, as long as you upgrade before the end of the year.

"We're in the time of year when customers are on the fence about buying a new phone – for fear that it'll be a generation old in just a few months," T-Mobile said.

"We're eliminating that worry completely for iPhone lovers."

You'll also be priority customers for when the next iPhone is released, with T-Mobile CEO, John Legere, saying, "When you order your upgrade during the first 48 hours it's available, we'll give your order priority and ship it first, along with others who qualify for priority access."

If you don't have an iPhone 6 yet, you'll need to sign up for one before Labor Day (September 7) to be eligible for a free iPhone upgrade this year.

Apple Music, too

T-Mobile is also giving Apple Music lovers the chance to stream the service for free - meaning it won't count against your data limit.

The Uncarrier says Apple Music has become the most requested addition for T-Mobile's Music Freedom feature, which lets you stream music from participating music streaming services for free.

Of course, you'll still need to subscribe to the service through Apple, but by adding the streaming radio service to Music Freedom, T-Mobile may be making it a more attractive offering for its customers.

• Check out our review of the iPhone 6