One way Apple will aim to keep the "iPhone 7" competitive is the addition of new fast-charge technology, according to one rumor.

The device will use improved circuitry supporting "at least" 5-volt, 2-amp charging, said @the_malignant, a Twitter user specializing in phone leaks. Current iPhone chargers are rated at one amp.

Many Android devices now offer some form of fast-charging, allowing them to hit a practical battery reserve in minutes instead of hours. The Samsung Galaxy S7 and S7 Edge, for example, can each go from 0 to 50 percent charge in about 30 minutes.

In fact current iPhones already use comparable technology, but nothing Apple has chosen to market as a feature. The company could be hoping to match or surpass rivals with the "iPhone 7."