$_POST['time_format'] = $_POST['time_format_custom'];
// Map UTC+- timezones to gmt_offsets and set timezone_string to empty.
if ( !empty($_POST['timezone_string']) && preg_match('/^UTC[+-]/', $_POST['timezone_string']) ) {
$_POST['time_format'] = $_POST['time_format_custom'];
// Map UTC+- timezones to gmt_offsets and set timezone_string to empty.
if ( !empty($_POST['timezone_string']) && preg_match('/^UTC[+-]/', $_POST['timezone_string']) ) {