Pantheon release notes

PHP versions 8.2.31, 8.3.31, 8.4.21, and 8.5.6 are now available on the platform. These updates include important security fixes, along with bug fixes and enhancements that improve performance and stability. Updates will be applied automatically over the next few days, so no manual action is required.

PHP 7.2, 7.3, and 8.0 have reached End of Sale on the Pantheon platform. New sites can no longer be created using these PHP versions.

This was previously announced in the PHP version removal schedule published March 11, 2026.

These versions, along with PHP 5.6, 7.0, and 7.1, are scheduled for removal on September 30, 2026. Sites still running a removed PHP version will be automatically upgraded to the oldest available PHP version at the time of removal.

Action required

If your site is running PHP 7.2, 7.3, or 8.0, upgrade to a recommended PHP version before September 30, 2026 to avoid disruption. Pantheon recommends PHP 8.3 or 8.4 for all production sites.

For guidance on upgrading, refer to Upgrade PHP Versions.

Sites created with custom upstreams that specify an end-of-sale PHP version may also experience unexpected behavior upon site creation.

PHP versions 8.4.20 and 8.5.5 are now available on the platform. These updates include bug fixes and enhancements that improve performance and stability. Updates will be applied automatically over the next few days, so no manual action is required.

Terminus 4.2.1 is now available. This patch release fixes a pagination bug affecting org:site:list and a WordPress-specific issue.

Key improvements in this release

• Fix incomplete site listings: org:site:list could return truncated results when the API returned short pages, affecting organizations with sites in supporting workspaces (#2829)
• WordPress fix: Only include wp_replace_siteurl if the site is WordPress (#2825)

How to upgrade to Terminus 4.2.1

If you use Homebrew (macOS-only) to manage your Terminus installation, you should upgrade using:

If you installed Terminus directly from the .phar file, you should upgrade using the self:update command:

For more information about this release, visit the GitHub release page.

If you have questions or concerns around Terminus, please use the Terminus issue queue.

Sites with Multizone Failover enabled are now eligible for the Global CDN (GCDN) Beta. Previously, Multizone Failover sites were excluded from the Beta — that restriction has been removed.

What's changed

• Multizone Failover is no longer listed as an excluded configuration for the GCDN Beta.
• Eligible Multizone Failover sites will see the GCDN Beta banner in the Pantheon site dashboard.

No action is required. If you operate a Multizone Failover site, simply look for the GCDN Beta banner on your site dashboard and follow the guided steps when you're ready to migrate.

More information

For full details on the GCDN Beta, see the GCDN Beta documentation.

As previously announced, Tika 1.18 and 1.21 have been removed from the Pantheon platform. All sites now run Tika 3 regardless of the tika_version setting in pantheon.yml.

Action Required

• If you have not already done so, remove tika_version: 1 from your pantheon.yml before May 12, 2026.
  • Any tika_version: 1 entries will be ignored until May 12, 2026, at which point they will be rejected and prevent deployments.
• Update the used Tika 1.x path to Tika 3, for details see related documentation.
  • Existing Tika 1.x file paths will continue to symlink to the new Tika 3 location for the time being, but these symlinks will be removed at a later date.

The Pantheon MU Plugin v1.5.6 is now available.

WordPress sites can apply this update by applying upstream updates from the dashboard or via Terminus. WordPress (composer managed) sites can upgrade using composer update or by checking for updates in the dashboard.

Revised MU Plugin update strategy

Starting with this release, MU Plugin updates are deployed as standalone commits to the WordPress upstream, independent of WordPress core version updates. WordPress sites will now receive MU Plugin updates more frequently and as discrete, visible changes in the dashboard — rather than bundled with core version bumps.

What's new?

This release spans two MU Plugin versions, with updates concerning WordPress sites running Elasticsearch on Pantheon:

1.5.5

• Fixes an issue where wp elasticpress sync CLI commands indexed content with http:// image URLs instead of https://, causing broken images on the HTTPS frontend. A pantheon_elasticpress_force_https_in_cli filter is available for sites that need to opt out of this behavior.

1.5.6

• Fixes ElasticPress Autosuggest and Instant Results on sites using ElasticPress.io by routing browser-side search requests to the public host rather than an internal proxy URL that browsers cannot reach.

WordPress upstream

• WP_HOME and WP_SITEURL definitions in wp-config-pantheon.php are now conditional, so customer-defined values are respected and PHP notices are no longer generated when these constants are already set before wp-config-pantheon.php is included.

As noted in our June 2025 release note, Drush 5 and 7 are no longer available on Pantheon, and pantheon.yml files retaining these retired values would eventually cause a git push to be rejected. That enforcement is now in effect.

Pantheon now rejects git push when drush_version is set to 5 or 7 in pantheon.yml. The supported values are 8, 9, and 10.

Validation runs whenever pantheon.yml changes are detected on push, including reverts. Sites with drush_version: 5 or 7 already committed are unaffected until the file is modified. A git revert or git reset that touches pantheon.yml will also trigger validation and be rejected if the retired values are present.

Action required

Customers with sites configured for Drush 5 or 7 should upgrade the Drush version in pantheon.yml to at least Drush 8:

Sites created with custom upstreams using these versions may also encounter errors on site creation or upstream updates if drush_version is still set to 5 or 7.