What is the passcode character limit in ios 10

I have never seen any place where Apple documents any upper limit for a complex passphrase. The numeric passcodes are limited to 4 or 6 digits. But the complex passphrases can be much longer (mine is currently 13 characters long). However, I don't know just how long.

Lifewire and AppleInsider have had articles claiming an upper limit in iOS of 37 characters, but I have never confirmed that number. That would give you 77^37 possible combinations.