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 April 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 set your PHP Runtime version
New sites on the platform are provisioned with the latest PHP Runtime, Generation 2. Sites that do not specify the PHP Runtime Version in pantheon.yml are set to use Generation 2.
To revert to the previous PHP Runtime, add the following to your pantheon.yml:
Timeline
| Phase | Date | Details |
|---|---|---|
| Beta | May - September 16, 2025 | Environments could be opted-in. All other environments remained on the previous generation. |
| New Sites | September 17, 2025 | New sites created on the platform use PHP Runtime Generation 2. |
| Gen 2 Rollout | September 24 - November 20, 2025 | A 60-day rollout gradually upgraded sites to PHP Runtime Generation 2. An opt-out is available. |
| 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 Gen 1 is removed and all sites are auto-upgraded.
The table below details the dates for the Gen 1 removal.
| Start Date for Auto-Upgrades | Site Plans | Environments |
|---|---|---|
| April 6, 2026 | All Plans | Dev/Multidevs |
| April 13, 2026 | All Plans | 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 | 3.2 |
| PhantomJS | 1.7.0, 2.1.1 available | Not available |
1 Support for this OS Package will be added soon. If you depend on this OS Package, remain on PHP Runtime Generation 1 for now.
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 | 6.3.0 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 |
1 Review the TLS documentation to check which version of TLS your external connections are using, and how to ensure you are compatible with this change.
Reporting Issues
If you encounter any issues with PHP Runtime Generation 2:
- Check the Known Changes and Requirements 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 to be compatible with Generation 2?
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 switch back to PHP Runtime Generation 1?
You may switch to PHP Runtime Generation 1 by setting the following in your pantheon.yml:
Note: All sites on Generation 1 will be auto-upgraded to Generation 2 starting April 6, 2026, if they haven't already.
Q: Can I be excluded from the removal of PHP Runtime Generation 1?
All sites on Generation 1 will be auto-upgraded to Generation 2 starting April 6, 2026, if they haven't already. The rollout will not have an exclusion policy for the auto-upgrades.