Pantheon release notes

We’ve replaced all 5xx error messages with plain HTML and removed Pantheon branding for sites hosted on Pantheon.

Why this change

Many of our customers, particularly those who are clients of our agency partners, may not be aware that their sites are hosted on Pantheon. For these clients, encountering Pantheon branded error messages could lead to confusion.

What’s changed

• Removal of Pantheon branding and Zeus graphic.
• Updated HTML to support the new messages.

The latest 1.4.2 update of the Pantheon MU Plugin is now available. This update fixes a bug in the pantheon_cache_default_max_age filter added in 1.4.0 where the filtered value was not being used in the cache control headers. This bug was found by Brian Perondi and surfaced in our Community Slack Workspace. We appreciate the report and the fix will be available with the next WordPress release. Composer-based WordPress installs can get the update right away by running composer update.

Beginning on May 20th, Pantheon will start enhancing our platform's scalability with an update to our traffic delivery and load balancing systems. These improvements, rolling out over the next few weeks, require no action from you.

Our new solution, built on AlloyDB, will make Pantheon more resilient to traffic spikes, including potential DDoS attacks. We’re introducing this change gradually, starting with a small percentage of traffic (less than 0.1%), to ensure maximum safety. Our engineering team will closely monitor the process and can quickly revert to the previous system if needed.

We expect that you will not notice any changes during this update, but it will result in increased reliability for your site. Once the rollout is complete and we’ve gathered data, we’ll share a detailed analysis of the benefits this upgrade brings to our platform.

PHP 8.2.19, and 8.3.7 were released on the platform. They contain the latest bug fixes for PHP.

As a reminder, PHP 8.0 reached End-of-Life on 26 November 2023. For the best performance and security, Pantheon recommends running PHP 8.2 and above.

Beginning this week, Pantheon will start transitioning individual WordPress and Drupal sites to use Sendgrid's API for the delivery of outgoing email initiated by these CMSes. We expect all sites to be fully transitioned by May 31, 2024. This change is happening at the platform level, not within the CMS code or configuration, and therefore requires no action by customers.

Reason for transition

The transition aims to enhance the reliability and deliverability of transactional emails. Historically, Pantheon has relied on a local MTA (postfix) to send these messages, which has led to common issues such as emails being categorized as spam or failing to deliver. By switching to SendGrid's API, we aim to reduce these issues and enhance the overall email delivery experience for our customers.

WordPress and Drupal core can trigger transactional emails for actions such as "Forgot Password", which allows users to reset their password after receiving an email.

For teams for whom the delivery of such transactional emails is critical to operation, we have recommended using third-party services and continue to do so even as we enhance the reliability of our platform-level emails with this switch to SendGrid.

This change should not be noticeable by most customers aside from the increased reliability of emails initiated by WordPress and Drupal.

WordPress 6.5.3 is now available on the platform.

Highlights

• 12 bug fixes in Core
• 9 bug fixes for the block editor

You can review a summary of all the updates in the 6.5.3 release candidate announcement.

The New Relic PHP agent has been updated to the latest version (v10.19.0.9). Compared with the previously available version on the platform (v10.10.0.1), some of the changes and fixes include:

• Drupal 9.4+ now reports hooks and modules (see below for more details)
• Resolved erroneous deprecation warnings for PHP 8.1+
• Support for PHP 8.3

See the complete New Relic PHP agent changelog for more details.

Learn More about New Relic, real-time performance monitoring for your Pantheon web applications.

Action Required: Default behavior of New Relic Drupal metrics has changed

Pantheon no longer supports Drupal-specific metrics in New Relic by default. However, the functionality is still available. If this is crucial for troubleshooting your sites, please add these lines to your site’s pantheon.yml file to enable this reporting:

Our support team is happy to help if you have any questions or need assistance.

Effective May 1, 2024, Pantheon began to enforce a monthly limit of synthetics checks for each Pantheon account (excluding ping checks).

• Each Pantheon account can run up to 10,000 New Relic synthetic checks per month (unlimited number of ping checks).
• Pantheon provides a monthly shared number of synthetic checks for all Pantheon customers.
• To ensure that all Pantheon users can use Synthetics, we ask customers to reduce their checks to <10,000 per month per Pantheon account.
• After May 1, 2024, Pantheon will take action by reducing the number of synthetic checks in Pantheon accounts exceeding 10,000 checks per month.
• Pantheon will not delete synthetic monitors or historical data but will reduce the frequency and the number of locations where a synthetics monitor orginates from.