PHP Runtime Generation 2
The second generation of Pantheon's PHP runtime provides added security and updated extensions.
Overview
The new generation of Pantheon's serverless PHP runtime represents our commitment to providing a modern, secure, and efficient PHP runtime for your websites.
Depending on your website's features, this new PHP runtime may have major effects on the operation of your site. The previous generation will be removed in early 2026.
What's included?
- Long Term Support (LTS) coverage for EOL PHP versions (PHP 5.6+)
- Better CMS functionality via updated PHP extensions
- PHP 8.4 availability
How to upgrade manually
To enable the second generation PHP runtime for an environment, add the following to your pantheon.yml:
php_runtime_generation: 2To safely revert to the previous generation, use the following:
php_runtime_generation: 1Since any pantheon.yml changes are part of your site repository and promoted if you push to test or live, we recommend using a multidev or removing the php_runtime_generation parameter before promoting any code while you are testing compatibility.
Timeline
| Phase | Date | Details |
|---|---|---|
| Beta | May - September 16, 2025 | Environments can be opted-in. All other environments will remain on the previous generation. |
| New Sites | September 17, 2025 | New sites created on the platform will use PHP Runtime Generation 2. |
| Gen 2 Rollout | September 24 - November 20, 2025 | A 60-day rollout will gradually upgrade sites to PHP Runtime Generation 2. Sites may be opted-out. |
| Gen 1 Removal | April 6 - 17, 2026 | PHP Runtime Generation 1 will no longer be available. All remaining sites will be auto-upgraded. |
Current Phase Details
We have completed the initial Gen 2 Rollout. Sites may continue to opt-out until the Gen 1 Removal phase takes place.
The table below contains the dates we upgraded sites to Gen 2 that were not set to opt-out.
| Start Date for Upgrades | Site Plans | Environments |
|---|---|---|
| September 24 | Sandbox | Dev/Multidevs |
| October 14 | Sandbox | Test/Live |
| October 16 | Basic | Dev/Multidevs |
| October 29 | Performance/Elite | Dev/Multidevs |
| November 3 | Basic | Test/Live |
| November 17 | Performance/Elite | Test/Live |
Once the Dev environment for a site has been upgraded to Generation 2, deploying commits from Dev to Test will automatically upgrade the Test environment to Generation 2 as well. Following this pattern, an upgrade to the Live environment takes place once commits are deployed from the Test to Live environment.
Known Changes and Requirements
OS Packages
| Package | Gen 1 | Gen 2 |
|---|---|---|
| IBM PHP ODBC Driver | Available for PHP 7.4-8.2 | Coming soon 1 |
| wkhtmltopdf | Available | Not available - switch to dompdf |
| Apache Tika | 1.18, 1.21 | 1.18, 1.21, 3.2 |
| PhantomJS | 1.7.0, 2.1.1 available | Not available |
PHP Extensions
| Extension | Gen 1 | Gen 2 |
|---|---|---|
| ioncube | Available for PHP 7.1 only | Not available |
| pdo_sqlsrv | Available for PHP 7.2 only 5.2.0 | Coming soon for PHP 8.2+ |
| curl | v7.61.1 | 7.88.1 |
| gd | 2.1.0 | 2.3.3 |
| iconv | 2.28 | 2.36 |
| mongodb | 1.14 | 2.1.1 |
| openssl | 1.1.1k | 3.0.17 |
| pdo_pgsql | 13.5 | 15.14 |
| pdo_sqlite | 3.26.0 | 3.40.1 |
| pgsql | 13.5 | 15.14 |
| redis | 5.3.7 Compression types: zstd | 6.2.0 Compression types: zstd, lzf, lz4 |
| sqlite3 | 3.26.0 | 3.40.1 |
Networking
| Protocol | Gen 1 | Gen 2 |
|---|---|---|
| TLS | 1.0-1.3 | 1.2-1.3 1 |
Known Issues
- Drupal 8+ sites using Solr 3 are not compatible with PHP Runtime Generation 2. Upgrading to Solr 8 or disabling Solr is required. These sites were not included in the initial automatic upgrade rollout. The dev/multidev environments of these sites will be upgraded on December 9, and the test/live environments will be upgraded on December 16. Opting out of Generation 2 is still available for these sites.
Reporting Issues
If you encounter any issues with PHP Runtime Generation 2:
- Check the Known Issues section above
- Verify the issue is related to the new PHP runtime by reverting back to
1in yourpantheon.ymlfile. - Submit a detailed report through our Support Portal. Include "PHP Runtime Generation 2" in your message to support.
Frequently Asked Questions
Q: How can I determine which PHP runtime a site environment is using?
The PHP runtime is set at the environment-level. You can find out which generation an environment with the following methods:
- Use the Terminus command
terminus env:info <site>.<env>. This requires Terminus 4.0.2+ - Use the Terminus command
env:list <site> --fields=id,php_runtime_generation,php_version. This requires Terminus 4.1.0+ - View your site on the Pantheon Dashboard, navigate to the environment's Status page, then review the Software Versions block
Q: Will I need to make changes to my website?
Potentially. Depending on your integrations with our PHP extensions and operating system libraries, you may need to update your website to be compatible with new PHP runtime.
Q: How do I opt out of PHP Runtime Generation 2?
You may opt-out of the platform rollout by setting the following in your pantheon.yml:
php_runtime_generation: 1Note: All sites will be auto-upgraded starting April 6, 2026, if they haven't already, including sites that specify the opt-out above.
Q: Can I switch back to the previous PHP runtime if I encounter issues?
Yes, you may revert back to the first generation PHP runtime by setting the following in your pantheon.yml:
php_runtime_generation: 1Q: After upgrading to PHP Runtime Generation 2, I removed php_runtime_generation from my pantheon.yml but the environment did not go back to Generation 1. How do I downgrade?
To revert back to the first generation PHP runtime, you must set the following in your pantheon.yml:
php_runtime_generation: 1