Benjamin Mayo, writing for 9to5Mac:

The iPhone 7 had been rumored to be dropping the analog 3.5 mm headphone jack, in favour of wireless Bluetooth or Lightning cable headphones for audio output. However, a new iPhone 7 component leak posted on Weibo disagrees with previous reports, depicting a board that includes a 3.5mm jack.

And:

The pictured board is sized for a 4.7 inch sized iPhone (and an equivalent version for the 5.5 inch phone has not surfaced) so there’s a possibility the 3.5mm jack will stay on the smaller sized phone but be dropped on the Plus models. This strategy does not sound very ‘Appley’ — it makes more sense for it to deprecate technologies consistently across the lineup.

Moving on from the 3.5mm analog jack makes sense to me. It’s universal technology, but an antiquated relic in digital signal path. This move is inevitable, at some point.

Keeping the 3.5mm jack makes sense. Everyone has headphones that “just work” with this technology and a move to wireless will relegate all those headphones to the dustheap.

One model with and one model without? That’s the one possibility that doesn’t click.