We're approaching this story with a good deal of caution, perhaps appropriately as one might approach an unexploded bomb - ie: preferably remotely by the use of some kind of drone, or at worst a long stick.
The news follows on from the Samsung Galaxy Note 7 debacle where exploding batteries caused the Korean OEM to engage in a mass recall of millions of devices (and at considerable cost - an estimate $1.5bn loss, in fact). According to a post on Reddit, reported via Mydrivers, Apple's iPhone 7 may not be immune to the possiblity of spontaneous combustion.
Now this is where things get shaky. All we have to go on is the word of one guy and some pictures he's posted of an iPhone that is clearly fried. This does of course raise questions of authenticity, feasibly this could be a deliberate hoax in which someone threw an iPhone in an oven, or something. But taking it at face value, this guy is saying his iPhone 7 blew up, he didn't explain how or any other details about the situation, other than to say "at least the packaging didn't catch fire," under the title "Running a little hot".
The photos show some visible charring, cracking, and discolouration, as well as the display and rear panel having popped off. While the box might not have caught fire there is also clearly some staining and damage sustained from the incident; according to the poster's other comments he says the incident may have happened "between the factory and delivery", implying he opened the box to find this mess.
As the incident is thus far an isolated one, we haven't seen any comment from Apple on the subject. We'll be sure to keep you posted if we hear of any other exploding iPhone 7 incidents.