Based on the photo leaked on Chinese site Weibo (see above), a toggle to enable and disable the ringer cannot be seen in its usual location above the volume buttons. This is the first time the removal of the mute switch has been floated and given the source's provenance, it should be treated with some caution.
Benjamin Mayo at 9to5Mac reported that this could be the first time that removing the mute switch from the iPhone has been raised as a possibility.
Mayo observed that Apple has slowly been removing the mute switch from its iOS devices. Beginning with the iPad Air 2, all new iPads have not included a mute switch. This is somewhat understandable for a tablet where the primary use case does not include alarms or ringing alerts.
For a phone however, the mute switch has been a defining feature of the iPhone since its inception. It would be crazy if Apple removed it ... but that is what the latest pictures suggest. Nevertheless, most Android phones do not include mute switches and instead rely on software toggles to activate or silence the ringer. Maybe Apple believes the new Control Center in iOS 10 is good enough that a hardware switch is no longer necessary.
The photos also suggest that the iPhone 7 could feature a Smart Connector, which could allow users to pair their phones with accessories like keyboards.