Title: WordPress critical problem: date_default_timezone_set ()
Last modified: July 9, 2020

---

# WordPress critical problem: date_default_timezone_set ()

 *  Resolved [stencil56](https://wordpress.org/support/users/stencil56/)
 * (@stencil56)
 * [5 years, 10 months ago](https://wordpress.org/support/topic/wordpress-critical-problem-date_default_timezone_set/)
 * The default time zone is not valid.
    PHP’s default time zone has changed after
   loading WordPress for a call of the date_default_timezone_set () function. This
   interferes with the correct date and time calculations.
 * All is set up correct: newest wordpress release, theme up to date, all plugins
   up to date.
    When i deactivate your plugin (Wpdevart Booking Calendar) all works
   fine. The entry can be found in your booking_calendar.php (line 197).
 * Glad if you have a fix for it to get the right time in the output, without the
   date_default_timezone_set () function.
 * Cheers

Viewing 8 replies - 1 through 8 (of 8 total)

 *  Plugin Author [wpdevart](https://wordpress.org/support/users/wpdevart/)
 * (@wpdevart)
 * [5 years, 10 months ago](https://wordpress.org/support/topic/wordpress-critical-problem-date_default_timezone_set/#post-13104252)
 * Hi dear user.
 * Okay, we will check it and then we will let you know.
 * Thanks.
 *  Plugin Author [wpdevart](https://wordpress.org/support/users/wpdevart/)
 * (@wpdevart)
 * [5 years, 10 months ago](https://wordpress.org/support/topic/wordpress-critical-problem-date_default_timezone_set/#post-13142481)
 * Hi dear user.
 * Sorry for the late response.
 * WordPress timezone setting doesn’t change the timezone and our calendar, and 
   times in the calendar doesn’t work correctly.
 * Thanks.
 *  Thread Starter [stencil56](https://wordpress.org/support/users/stencil56/)
 * (@stencil56)
 * [5 years, 10 months ago](https://wordpress.org/support/topic/wordpress-critical-problem-date_default_timezone_set/#post-13166326)
 * Hello there.
 * Wordpress timezone settings works as for default with wordpress using UTC as 
   standard timezone and the offset for European time with the (Wpdevart Booking
   Calendar) plugin deactivated. If the plugin is activated this causes a error 
   within wordpress setting the timezone to utc without offset because of the PHP
   function call in your plugin “date_default_timezone_set ()”. (Timezone in the
   calendar also set to UTC without any offset recognized).
 * Any workaround to get this fixed?
 * Thx in advance.
 *  Plugin Author [wpdevart](https://wordpress.org/support/users/wpdevart/)
 * (@wpdevart)
 * [5 years, 9 months ago](https://wordpress.org/support/topic/wordpress-critical-problem-date_default_timezone_set/#post-13204684)
 * Hi dear user.
 * Sorry for the late response.
 * We will check it again and then we will let you know.
 * Thanks.
 *  Plugin Author [wpdevart](https://wordpress.org/support/users/wpdevart/)
 * (@wpdevart)
 * [5 years, 9 months ago](https://wordpress.org/support/topic/wordpress-critical-problem-date_default_timezone_set/#post-13221636)
 * Hi dear user.
 * We updated our plugin, can you check if the last version works fine?
 * Thanks.
 *  Thread Starter [stencil56](https://wordpress.org/support/users/stencil56/)
 * (@stencil56)
 * [5 years, 9 months ago](https://wordpress.org/support/topic/wordpress-critical-problem-date_default_timezone_set/#post-13231390)
 * Hello there
 * So far the offset for europe from utc is working for me with the new update.
   
   The error (The default time zone is not valid. PHP’s default time zone has changed
   after loading WordPress for a call of the date_default_timezone_set () function.
   This interferes with the correct date and time calculations.) in wordpress persists.
   Since the last wordpress update (earlier this year) wordpress doesnt accept the“
   date_default_timezone_set” PHP function. Hope you get it fixed in a later update.
 * Thx for the patch off the offset.
 * Have a good time.
 *  Plugin Author [wpdevart](https://wordpress.org/support/users/wpdevart/)
 * (@wpdevart)
 * [5 years, 9 months ago](https://wordpress.org/support/topic/wordpress-critical-problem-date_default_timezone_set/#post-13264669)
 * Hi dear user.
 * We will try to fix it in the future.
 * Thanks a lot.
 *  Thread Starter [stencil56](https://wordpress.org/support/users/stencil56/)
 * (@stencil56)
 * [5 years, 9 months ago](https://wordpress.org/support/topic/wordpress-critical-problem-date_default_timezone_set/#post-13298084)
 * Hello
 * Thanks for the reply. I think we can close it for now.
 * Greetings

Viewing 8 replies - 1 through 8 (of 8 total)

The topic ‘WordPress critical problem: date_default_timezone_set ()’ is closed to
new replies.

 * ![](https://ps.w.org/booking-calendar/assets/icon-128x128.png?rev=1307202)
 * [Booking calendar, Appointment Booking System](https://wordpress.org/plugins/booking-calendar/)
 * [Frequently Asked Questions](https://wordpress.org/plugins/booking-calendar/#faq)
 * [Support Threads](https://wordpress.org/support/plugin/booking-calendar/)
 * [Active Topics](https://wordpress.org/support/plugin/booking-calendar/active/)
 * [Unresolved Topics](https://wordpress.org/support/plugin/booking-calendar/unresolved/)
 * [Reviews](https://wordpress.org/support/plugin/booking-calendar/reviews/)

## Tags

 * [date_default_timezone_set](https://wordpress.org/support/topic-tag/date_default_timezone_set/)

 * 8 replies
 * 2 participants
 * Last reply from: [stencil56](https://wordpress.org/support/users/stencil56/)
 * Last activity: [5 years, 9 months ago](https://wordpress.org/support/topic/wordpress-critical-problem-date_default_timezone_set/#post-13298084)
 * Status: resolved