When will the next 5.5 inch iPhone come out?

I'm tired of my 5s and ready to sign a new 2 year contract, but I want the latest and greatest when I do upgrade.

In, September

You can buy a new phone at any time during your "contract". Granted if your are making installment payments on your phone, you will be forced to pay full retail for that replacement phone. But if your phone is paid for, nothing stops you from buying the latest and greatest today, next week, or when the new ones show up at the stores.

IPhones launch every year in September.

September.