Samsung upped the ante last year, by releasing IP68-certified flagships like the Galaxy S7 and S7 egde, which can be submerged in up to five feet of water for half an hour. Granted, Sony has been making waterproof flagships long before that, but it has nowhere near the market share of the S-series, so the S7 was a watershed moment (pun intended). Apple didn't wait long, and introduced its iPhone 7 and 7 Plus with waterproof certification of their own for the firs time since the line started in 2007.
The iPhones are IP67-certified, though, meaning that water protection is valid at up to three feet instead of the S7's five feet, but still you shoudn't be worried when you use the phone in the rain, shower, or it swirls down to the bathtub drain, and these are the most practical scenarios for a waterproof phone anyway. This year, however, marks the 10th anniversary of the iPhone, and Apple is rumored to go all out with a special OLED edition that will reportedly be "edge-to-edge" and a sight to behold. For the regular model upgrades, however, it has also gone all-out, tip insider sources, and all 2017 iPhone will allegedly sport IP68 certification for freestyle waterboarding.
In addition, the Galaxy S8 is now tipped to have the same waterproofing level like the S7 and S7 edge, so this year will see the two most popular phone lines come with the IP68 stamp, good times. The source also reiterates that Samsung has decided to waterproof all its new phones, down to the J line, which is one of its most popular and widely sold family. Apple and Samsung are using tape for sealing their phones, instead of copious amounts of adhesive, which aids repairability in restoring the phones back to their original water and ingress protection level when you bring them for screen replacements and the like.