PHP version switching not working

DevKinsta Application Support
1

The PHP version switching feature in DevKinsta is not working. Despite setting a site to use PHP 8.3 in the DevKinsta interface, the actual containers continue to run PHP 7.4.33, preventing the use of PHP 8+ syntax in WordPress development.

Environment Details

  • DevKinsta Version: 2.13.4
  • Operating System: macOS
  • Docker Version: 28.3.2, build 578ccf6
  • Site Name: ncwit
  • Expected PHP Version: 8.3
  • Actual PHP Version: 7.4.33

Current Docker Images

All DevKinsta images are version 1.3.6 and appear to be 16 months old:

kinsta/devkinsta_mailhog      1.3.6      f060baef253c   16 months ago   392MB
kinsta/devkinsta_adminer      1.3.6      0e94ac87d142   16 months ago   94.8MB
kinsta/devkinsta_nginx        1.3.6      b123f3cff7e8   16 months ago   53.3MB
kinsta/devkinsta_db           1.3.6      fb86d6cbbb8a   16 months ago   397MB
kinsta/devkinsta_fmp          1.3.6      edc7803a86f1   16 months ago   647MB

Steps Taken to Reproduce/Fix

  1. Changed PHP version in DevKinsta interface:

    • Opened site settings in DevKinsta
    • Changed PHP version from 7.4 to 8.3
    • DevKinsta interface shows PHP 8.3 is selected

  2. Verified the issue:

    • Site runs correctly in browser
    • Container still shows PHP 7.4.33: docker exec -u www-data -it devkinsta_fpm bash then php -v
    • PHP 8+ syntax (like match expressions) causes parse errors

  3. Attempted complete rebuild:

    • Stopped site in DevKinsta
    • Quit DevKinsta completely
    • Removed all containers: docker stop and docker rm for all devkinsta containers
    • Removed all images: docker rmi for all kinsta images
    • Restarted DevKinsta and recreated site
    • Result: DevKinsta downloaded the same 1.3.6 images with PHP 7.4.33

  4. Checked for updates:

    • No updates available for DevKinsta application

Expected Behavior

When I set a site to use PHP 8.3 in the DevKinsta interface, the actual PHP runtime in the containers should be PHP 8.3, allowing the use of PHP 8+ language features.

Actual Behavior

The DevKinsta interface shows PHP 8.3 is selected, but the containers continue to run PHP 7.4.33. This creates a development/production environment mismatch since our production servers run PHP 8+.

Impact

  • Cannot use PHP 8+ syntax features in local development
  • Development environment doesn’t match production environment (PHP 8+)
  • wp-cli fails due to PHP syntax errors when code uses PHP 8+ features
  • Blocks local WordPress development workflow

Questions

  1. Are the 1.3.6 Docker images the latest available? If not, how can I force DevKinsta to download newer images?
  2. Is there a manual way to update the Docker images that DevKinsta uses?
  3. Should PHP version switching work with the current version of DevKinsta? If so, what might be preventing it from working correctly?
  4. Are there any configuration files or settings I can check/modify to troubleshoot this issue?
  5. Is there a recommended alternative for local WordPress development with reliable PHP 8+ support?

Please let me know what additional information or diagnostic steps would be helpful to resolve this issue.