Pantheon release notes

Editorial note: These updates were completed and deployed to the platform on December 23rd 2025.

PHP versions 8.1.34, 8.2.30, 8.3.29, and 8.4.16 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 8.4 is only available with the new PHP Runtime Generation 2.

The PHP 8.4 upgrade process automatically includes an upgrade to PHP Runtime Generation 2 if your site hasn't been upgraded already.

Important PHP version information

• PHP 8.1 and 8.2 are currently receiving security-only updates.
• For more details, see the full list of PHP supported versions.

For the best performance and security, Pantheon recommends running PHP 8.2 and above.

The phpredis extension has been updated to the latest version, 6.3.0, for environments using PHP 7.4+ on PHP Runtime Generation 2.

To view the latest improvements and fixes, view the changelog on GitHub.

Key changes

Collection metadata and publishing configurations are now managed via the Content Dashboard:

• Go to "Collection Settings > Metadata" in the Content Dashboard to manage custom metadata fields for a given collection.
  • Previously, this was done from the Google Docs Add-on via "About this collection > Page Metadata".
  • New metadata field capabilities have also been added, such as ordering fields or specifying both their label and their machine name independently.
• Use the entirely new "Collection Settings > Publishing" tab in the Content Dashboard to enable the following within the Google Docs Add-on for contributors across this collection:
  • Sections
  • Google Docs tabs

For details, see related documentation.

Additional changes

Bug fixes and other recent minor updates

• Starter kits and all Next.js applications have been updated to mitigate CVE-2025-55182 and CVE-2025-66478.
• The Ingest API previously only authorized Google accounts, but now accepts any authenticated user.
• Refactored the sign-in and sign-up experience for a smoother onboarding process including email verification. Country, state and other dropdowns now support keyboard navigation.
• Helper text added to collection creation for clarity. The playground guide also got improved with simplified navigation.
• SDK status endpoint no longer exposes version information for security reasons.
• Fixed glitch in component editor text fields that prevented input on some occasions.
• Disconnecting documents from collection now works as expected for content contributors.
• Fixed infinite page reload when navigating from add-ons to the collection structure.
• Preview now allows comparing published and submitted versions when reviewing content sent for approval.
• Permission menu entry in the Content Publisher dashboard is hidden for first-time users until a collection is created.
• The smart component add-on interface now clearly indicates when no components are configured, avoiding users to lose time trying to use a capability not yet configured.
• As well as several minor UX fixes and improvements

Log forwarding for Splunk and Sumo Logic is now availble via a Private Beta program. There is no additional cost for this feature and anyone can request an invite by submitting this form.

For more information, see this related blog post.

When enabled, this feature streams the following log types from your Pantheon site to your external service (Splunk or Sumo Logic):

• php-fpm-error
• php-slow
• php-error
• nginx-access
• nginx-error

Share feedback: Once Beta access has been granted, users will recieve a welcome email and be invited to a dedicated slack channel where you can provide feedback, ask questions and discuss usage with the Pantheon product and engineering team.

To request an invite, submit this form.

Documentation

See also, the following new docs:

• Log Fowarding Overview
• Sumo Logic Setup
• Splunk Setup

The new Site Dashboard is now available for all Workspaces. Today's release switches Personal Workspaces over to the new experience, a change we recently completed for Professional Workspaces.

The following ON/OFF toggles have been removed from the user interface:

• Personal Workspace > Site list "Open sites in new beta"
• Professional Workspace > Site list "Open sites in new beta" (removed in a previous release)

• Same functionality, familiar workflows – No need to relearn anything. Your day-to-day tasks remain unchanged.
• Modern, accessible design – We’ve made significant improvements to align with the latest usability design standards, enhancing readability, contrast, and navigation.
• Performance improvements under the hood – While this may feel mostly visual, we’ve reworked key infrastructure for long-term speed and reliability.
• Small but powerful UX upgrades – New conveniences like one-click to copy the commit SHA, along with other thoughtful touches for enhanced usability.

Following the successful rollout of PHP Runtime Generation 2 for all environments that have not opted-out, we are now preparing to remove PHP Runtime Generation 1 from the platform starting April 6, 2026.

What's changing when?

Between April 6 and April 17, 2026, all environments that have not been upgraded will be auto-upgraded to Generation 2. Opting out will no longer be available.

Action Required

Please view the Known Changes and Requirements list if you are still in the process of upgrading your site. We recommend all site owners proactively test and upgrade to Generation 2 rather than waiting for this auto-upgrade.

PHP versions 8.3.28 and 8.4.15, are now available on the platform. These updates bring the latest bug fixes, improving performance and security for your sites. The latest versions have already rolled out to all sites.

PHP 8.3.28 is available on both PHP Runtime Generation 1 and PHP Runtime Generation 2.

PHP 8.4 is only available with the new PHP Runtime Generation 2.

We are removing ionCube support from the platform on March 8, 2026. This PHP extension was prevously only available for PHP 8.1 on PHP Runtime Generation 1.

Pantheon continually reviews our PHP runtime and explores opportunities to optimize performance and build times.

If your application uses ionCube, please contact support or your Customer Success Manager to explore options for your use case.