Upgrading PHP to Handle 2026 Canadian Daylight Saving Time

About the Canadian Time Zone Transition

On November 1, 2026, parts of Canada will permanently transition to daylight saving time, abandoning the seasonal practice of falling back to standard time.

• Older PHP versions (8.3 and earlier) rely on outdated internal IANA timezonedb tables. 
• Without an update to the newer PHP version (8.4 or above), server-side functions tracking Canadian time coordinates will calculate incorrect timestamps starting November 1st.

Resolution

If your Drupal site uses a Canadian timezone setting (for example, under admin/config/regional/settings), please review its PHP environment settings immediately to ensure compliance with the upcoming Canadian time zone adjustments.

We are advising teams running older PHP versions (such as PHP 8.2/8.3) to update to either PHP 8.4 or 8.5. This update includes the necessary timezonedb database changes stemming from the permanent shift in Manitoba's, British Columbia’s, Northwest Territories’ and part of Ontario’s time offset. 

This may disrupt site operations, including but not limited to: scheduling scripts, e-commerce transaction logs, API data synchronization, and localized user notifications for any workflows interacting with other timezones.

Recommended Actions:

1. Check your runtime version: Run php -v via the CLI or check your environment configuration.
2. Upgrade Target: Deploy PHP 8.4 or PHP 8.5 starting with your development & staging environments. After testing, deploy it to your production environment.

If the site’s PHP version can’t be upgraded, an workaround is to try updating Drupal core’s setting under admin/config/regional/settings to a timezone that matches the jurisdiction’s timezone. Note, some Drupal configuration and modules could implement their own timezone overrides, each of which will need review and changes.

References:

• https://en.wikipedia.org/wiki/Daylight_saving_time_in_Canada
• https://www.php.net/manual/en/timezones.php