Warning: date(): It is not safe to rely on the system's timezone settings.

Warning: date(): It is not safe to rely on the system's timezone settings. You are *required* to use the date.timezone setting or the date_default_timezone_set() function. In case you used any of those methods and you are still getting this warning, you most likely misspelled the timezone identifier.

 
修正方法：2 種

1. 在 php.ini 裏設定 date.timezone

date_default_timezone_set('Asia/Taipei');

2. 在程式碼裏使用 date_default_timezone_set() 函式

date.timezone = "Asia/Taipei"

Debian :

# vi /etc/php5/apache2/php.ini

CentOS :

# vi /etc/php.ini

References :
PHP 5.3.x 的 strtotime() 時區設定 警告訊息修正 - Tsung's Blog