PHP Runtime Generation 2 (Beta)
The second generation of Pantheon's PHP runtime with added security and updated extensions.
Overview
A new generation of our Serverless PHP runtime is available in beta. This upgrade represents our commitment to providing a modern, secure, and efficient PHP runtime for your websites.
Depending on your website's features, this change may have major effects on the compatibility of your site. During the beta phase, we invite you to test your site for compatibility and performance to ensure a seamless upgrade. The previous generation will be removed in 2026.
Why Upgrade?
- Long Term Support (LTS) coverage for EOL PHP versions
- Better compatibility with updated PHP extensions
- PHP 8.4 availability*
* For CMS compatibility details, see Supported PHP Versions.
Opt-In Beta Phase (April - September 17, 2025)
During the beta phase, you can opt in to test your sites on the new PHP runtime. The opt-in is environment-based, meaning you can trial the new PHP runtime without affecting your other environments. This allows you to:
- Verify your site's compatibility before the platform-wide rollout
- Test your deployment workflows
- Identify any potential issues early
- Provide valuable feedback to our team
How to Opt In
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, you may remove the line during the beta phase or use:
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 (Opt-in) | May - September 2025 | Environments can be opted-in. All other environments will remain on the previous generation |
| Rollout (Opt-out) | Beginning September 17, 2025 | A 40-day rollout will auto-upgrade all sites to PHP Runtime Generation 2. Opting out via the pantheon.yml parameter will be available |
| Gen 1 Removal | Q1 2026 | PHP Runtime Generation 1 will no longer be available - all remaining sites will be auto-upgraded |
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 | 0.12.5 available | Replacement coming soon 2 |
| Apache Tika | 1.18, 1.21 available | 1.18, 1.21, 3.2 coming soon 3 |
| PhantomJS | 1.7.0, 2.1.1 available | Not available |
2 wkhtmltopdf is no longer supported by its maintainers. We are working to offer a different solution for sites that use server-side PDF generation.
3 Tika will be made available before the platform-wide rollout in September.
PHP Extensions
| Extension | Gen 1 | Gen 2 |
|---|---|---|
| ioncube | Available for PHP 7.1 only | Not available 1 |
| pdo_sqlsrv | Available for PHP 7.2 only 5.2.0 | Not available 1 |
| curl | v7.61.1 | 7.88.1 |
| gd | 2.1.0 | 2.3.3 |
| iconv | 2.28 | 2.36 |
| mongodb | 1.14 | 2.1.0 |
| openssl | 1.1.1k | 3.0.16 |
| pdo_pgsql | 13.5 | 15.13 |
| pdo_sqlite | 3.26.0 | 3.40.1 |
| pgsql | 13.5 | 15.13 |
| redis | 5.3.7 Compression types: zstd | 6.2.0 Compression types: zstd, lzf, lz4 |
| sqlite3 | 3.26.0 | 3.40.1 |
Does your application require an OS package or PHP extension that is no longer available? Please reach out to us to discuss compatibility by contacting your Customer Success Manager or creating a support ticket.
Networking
| Protocol | Gen 1 | Gen 2 |
|---|---|---|
| TLS | 1.0-1.3 | 1.2-1.3 1 |
Known Issues
- ClamAV is currently unavailable. Support for ClamAV will be added after the platform-wide rollout begins. If you depend on ClamAV services, we recommend you opt out of PHP Runtime Generation 2 for now.
- Object Cache Pro installation via Terminus for standard WordPress configurations is currently unavailable.
- Workaround: Downgrade to PHP Runtime Generation 1, follow the installation procedure, then upgrade back to PHP Runtime Generation 2.
Reporting Issues
If you encounter any issues while testing your site with PHP Runtime Generation 2:
- Check the Known Issues section above
- Verify the issue is related to the new infrastructure by reverting back to
1in yourpantheon.ymlfile. - Submit a detailed report through our Support Portal. Include "PHP Runtime Generation 2 Beta" in your message to support.
Frequently Asked Questions
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 the upcoming platform rollout?
You may opt-out of the upcoming platform rollout by setting the following in your pantheon.yml:
php_runtime_generation: 1Note: All sites will be auto-upgraded in Q1 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, set the following in your pantheon.yml:
php_runtime_generation: 1