Rule of thumb… When a new update gets released. Never update your iOS or any OS for that matter. I always wait for their 2nd release (usually within a week or so).
“iPhone and iPad owners locked out of their devices because of a problem with Apple’s latest mobile operating system have been provided with a solution.
The iOS 9.3 update caused some older versions of the phones and tablets to require the IDs and passwords previously used to set them up.
Many people complained that their machines had become unusable because they had forgotten or did not know the details.”
Source: BBC
