Is passcode exactly 6 digits? I have a 7 digit number I normally use, but update seems to want exactly 6.

Settings/Touch ID & Passcode.

And note that you can also select Custom Numeric Code.

FYI, even though it says “alphanumeric” if you use ONLY numeric digits, only a numeric keypad will be presented … making entry of the digits easier.

Also, not sure of the max number of allowable digits, but I’ve successfully tested it with as many as twenty (20).

Once you choose “Passcode Options” …