All three iPhones rumored to be launched in 2017 will retain Lightning connectors with the addition of USB-C Power Delivery for faster charging, including an all-new OLED model with a larger L-shaped battery and updated 4.7-inch and 5.5-inch models, according to KGI Securities analyst Ming-Chi Kuo.

New 2H17 models may all support fast charging. We believe all three new iPhones launching in 2H17 will support fast charging by the adoption of Type-C Power Delivery technology (while still retaining the Lightning port). A key technical challenge lies with ensuring product safety and stable data transmission during a fast charge. In order to achieve that goal, we think Apple will adopt TI's power management and Cypress's Power Delivery chip solutions for the new iPhone models. We note the OLED version may have a faster charging speed thanks to a 2-cell L shaped battery pack design.

An excerpt from his latest research note obtained by MacRumors:

Kuo expects Apple to retain the Lightning port given it has a slightly slimmer design compared to a USB-C port, to sustain MFi Program licensing income from Lightning accessories, and because he believes USB-C's high-speed data transmission is "still a niche application" for iPhone.

The 12.9-inch iPad Pro already supports USB 3.0 speeds and fast charging with a Lightning to USB-C cable, while iPhones and other devices with a Lightning connector still transfer at USB 2.0 speeds.

Kuo's prediction comes just two days after The Wall Street Journal seemingly reported that at least one upcoming iPhone model would have a USB-C port instead of a Lightning connector. However, the report's wording was somewhat vague and sparked a lot of confusing reaction among the Apple community.

Apple's latest MacBook Pro models are equipped with Thunderbolt 3 ports, which share the same connector design as USB-C, while the 12-inch MacBook also has a USB-C port. Apple could still bundle a Lightning to USB-C cable with its next iPhones to allow for connectivity with those notebooks out of the box.