Pantheon release notes

The latest 1.4.4 update of the Pantheon MU Plugin and the 2024-06-04 release of the WordPress (Composer Managed) are now available.

The MU plugin update will be included with the WordPress 6.5.4 release.

What's new?

Pantheon MU Plugin 1.4.4

This update fixes the WordPress Multisite network setup process by by ensuring the correct instructions for WordPress Multisite setup on Pantheon environments are always shown. The MU plugin replaces the WordPress core network setup page with a custom page that provides instructions for setting up a multisite network on Pantheon and adds filters that allows the content to be changed.

This update also fixes some display issues to that page.

WordPress (Composer Managed) update

The 2024-06-04 WordPress (Composer Managed) (Early Access) release updates the configuration file filename displayed on the network setup screen to specify config/application.php to apply your configuration changes to (the Bedrock default), rather than the WordPress default wp-config.php. This is accomplished via a filter in the MU plugin's implementation of that admin page that allows the configuration file name to be modified.

This update is now available to all WordPress (Composer Managed)-based installs.

The WordPress (Composer Managed) update also includes a Composer script to automatically update the Composer platform.php value to match the version of PHP in your pantheon.yml. Note: Roots Bedrock does not support below PHP 8.0. This update is unrelated to WordPress multisites, but is included in the latest release for the WordPress (Composer Managed) upstream.

The new 2.0.0 release is now available for the Pantheon Advanced Page Cache WordPress plugin. This update makes significant changes to the UI of the Pantheon Page Cache admin settings page when installed on a Pantheon environment with the latest version of the Pantheon MU Plugin (1.4.3 or later).

Highlights

• UI improvements: The Pantheon Page Cache admin settings page simplifies the Cache Max Age setting, providing a dropdown with values for 1 week, 1 month and 1 year. If a different value was saved in the database, it will be displayed as "Custom" in the dropdown with a humanized representation of the time. This is an improvement over the base input in the Pantheon MU plugin which requires a value in seconds. These changes will be available when the 1.4.3 release of the Pantheon MU plugin is deployed alongside WordPress 6.5.4.
• Site Health integration: Pantheon Advanced Page Cache now integrates into the Site Health page in your WordPress admin. Tests are run and reported for your cache max age value and recommendations are made.
• Minimum WordPress version bumped to 6.4: This update requires WordPress 6.4 or later for integration with the Site Health page and usage of the new wp_admin_notice function. If you are running an older version of WordPress, the plugin will still function, but a warning will be given on the Plugins page and you will not benefit from the updated notices and Site Health checks.
• Max age updated if previously saved at 10 minutes: The previous cache max age default value was 600 seconds. We currently recommend a minimum of 1 week for best performance, especially when using Pantheon Advanced Page Cache (which will automatically flush the cache when content is updated). If you had previously saved the default value of 10 minutes, it will automatically be updated to 1 week when you update to this version and log into the WordPress admin.
• Integration with the pantheon_cache_default_max_age filter: Pantheon Advanced Page Cache supports the pantheon_cache_default_max_age filter added in the Pantheon MU Plugin 1.4.0. If you have set a default max age with the filter for your site, Pantheon Advanced Page Cache will respect that value and display it in the UI as a custom value.

Download the 2.0.0 update today from your WordPress admin or from the WordPress plugin repository. Composer-based WordPress sites can get the update by checking the version parameters in your composer.json (ensuring that the version string is set to "*" or "^2.0") and running composer update.

The latest 1.4.3 update of the Pantheon MU Plugin is now available. This update adds filters and CSS selectors on the Pantheon Page Cache page, allowing them to be customized with plugins and custom code. This update will be included with the next WordPress release. Composer-based WordPress installs can get the update today by running composer update.

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.