[Vtigercrm-developers] $default_timezone and a world of pain

[Alan Bell]

In short, always set $default_timezone in config.inc.php to UTC and all 
will be well.

in this file:
include/fields/DateTimeField.php
there is a function:
         static function getDBTimeZone() {
                    if(empty(self::$databaseTimeZone)) {
                         $defaultTimeZone = date_default_timezone_get();
                         if(empty($defaultTimeZone)) {
                                 $defaultTimeZone = 'UTC';
                         }
                            self::$databaseTimeZone = $defaultTimeZone;
                 }
                 return self::$databaseTimeZone;
         }

the effect of this is that if you have specified something like 
'Europe/London' in your config.inc.php then vtiger 6.2 will store all 
datetime fields in your system's default time zone rather than UTC. This 
looks like it is working OK for a while in the vtiger user interface. 
After daylight savings or British summer time happens then the system 
will mess up times that were saved with the other offset. It also 
completely messes up synchronisation with exchange/android/ipad/anything 
else because those all expect the system to store UTC internally.

$default_timezone basically performs two functions now, it is the 
default timezone for new users (or users who have no timezone specified, 
but I don't know how to do that) and it is also the database timezone, 
which is a bit scary. I can't see any reason why anyone would ever want 
the database to be storing times in anything but UTC, and especially not 
in a zone with daylight savings.

Alan.