The guard scans them using his smartphone (i Phone, Android or Blackberry OS10 onwards) during his tour.
Put self-adhesive, very low cost labels on every check point.
Maybe you felt the update runs slower, maybe a necessary app isn’t yet compatible with the new i OS, or maybe you just preferred the prior version of i OS, the reason for downgrading doesn’t matter.
A few things to keep in mind here: downgrading only works as long as Apple signs the prior version of i OS, which is typically a short window.
01/24/2016 (PST) When users buy a Premium Module Key, users should receive a receipt from Paypal. 07/19/2015(PST) The version 2-3 A-Key Hole TV has been released.
The version has fixed for black screen in the some devices.