Internet is still filled with complaints and memes about iPhone 6 "bending" scandal, which forced Apple to inctroduce a new reinforced aluminium on the 6S model - but now we can expect something more than that.
Mac Otakara claims that Apple is making their next device waterproof and dust-proof, just like some other Android phones (like Xperia series).
The Japanese blog has been right before, particularly in predicting the 4.7-inch iPhone 6, so there may be some weight to this. There were also tests of iPhone 6S and 6S plus under water and each mobile did well with surviving over an hour.