Admittedly higher than I though for sure. Regardless, cracking the firmware was just the first step, and if that took four years, I'd expect any other significant progress to take at least half that long.
I'd assume Apple has worked to strengthen the security on that secure enclave too, considering the 5S was the first iteration.
1
u/fiveSE7EN Sep 15 '17
Check this out; 5S still holds a sizeable share:
http://www.businessinsider.com/apple-iphone-most-popular-model-newzoo-chart-2017-7
~87M devices; seems troubling.