A "person familiar with the matter" told Reuters that Samsung has finished with its internal investigation into the whole exploding phone thing. The conclusion of the investigation is that the battery was the main reason why the phones were catching fire. That's the TL;DR version.
This same unnamed source indicates that Samsung will issue a more formal announcement regarding its findings on January 23 and, unsurprisingly, the company will take increased measures to avoid repeating the problem again.
You may recall (bad pun intended) that Samsung first tried to offer a non-exploding replacement to everyone who bought a Galaxy Note7, but they ultimately had to destroy all the recalled phones after even the replacements started catching on fire. It's all such a shame, considering that I really liked this phone. Let's hope the next generation can build on all the good stuff and leave this whole exploding battery thing in the past.