Three PHP and web server improvements in one release: a more efficient Apache processing model, cleaner PHP version transitions, and support for PHP versions that the rest of the hosting world quietly dropped years ago.
By default, Panelica runs Apache with the prefork MPM, which is the safest and most compatible option. The prefork model spawns one process per request and works with every PHP-FPM configuration out of the box.
Apache event MPM is an alternative that handles concurrent connections more efficiently -- especially under high load. Instead of tying up a full process for the lifetime of each connection, the event model uses a thread-based architecture that can serve many connections with far fewer memory-resident processes.
The upgrade is opt-in for a reason: some modules and edge-case PHP configurations behave differently under event MPM. To make the switch safe for existing sites, Panelica runs a customer-safe upgrade hook before switching: it checks each virtual host's configuration for known incompatibilities and flags anything that needs attention before applying the change.
To enable Apache event MPM:
- Open Server > PHP and Web Server in the panel.
- Find the Apache MPM setting under the Apache section.
- Switch from Prefork to Event.
- Review any compatibility warnings the panel displays before confirming.
- Apply. Apache restarts with the new MPM. Existing sites keep serving requests throughout.
If you are running a server with dozens of concurrent users or applications that generate many simultaneous connections, event MPM is worth testing. You can switch back to prefork at any time from the same screen.
Changing a domain's PHP version used to carry a small risk: if the old PHP-FPM pool did not shut down cleanly, you could end up with two pools both claiming the same socket, or a zombie process holding resources. The new transition is atomic.
When you change a domain's PHP version:
- The new PHP-FPM pool is created and started.
- The panel verifies the new pool is accepting connections.
- Nginx is updated to point to the new socket.
- The old pool is stopped and cleaned up.
If the new pool fails to start for any reason, the change is rolled back and the original pool continues serving the domain. There is no window where the site is down, and there are no zombie FPM processes left behind after a failed transition.
To change a domain's PHP version:
- Open Domains > your domain > Edit.
- Find the PHP Version dropdown.
- Select the target version.
- Save. The transition happens in the background. The domain stays live.
This was covered in the previous announcement thread about extended PHP coverage, but it is relevant to mention here too. PHP 5.6 through 7.4 are available as isolated Docker runtimes alongside native PHP 8.1-8.4.
The approach is a transparent shim: from the panel's perspective (and from the user's perspective), a Docker-backed PHP version looks and works identically to a native one. Site files stay in the standard home directory. Databases stay on the server's MySQL. The PHP version dropdown shows all available versions with a (Legacy) badge next to the Docker-backed ones.
Legacy versions are not installed by default. To add one:
- Open Docker Manager > PHP Runtimes.
- Select the version you need (5.6, 7.0, 7.1, 7.2, 7.3, or 7.4).
- Click Install. The runtime is pulled and configured.
- The version appears immediately in the PHP version dropdown on any domain.
This is useful for hosting applications that cannot run on PHP 8.x: older Magento installations, legacy WHMCS module setups, inherited codebases that would require significant refactoring to modernize. Rather than running a separate unmanaged server for these, they live in the same panel with the same isolation, the same monitoring, and the same backup coverage as everything else.
- PHP 5.6, 7.0, 7.1, 7.2, 7.3, 7.4 -- Docker runtime, available on demand
- PHP 8.1, 8.2, 8.3, 8.4 -- Native binary, installed by default
- PHP 8.5 -- Native binary, available (release candidate)
All versions run with per-user PHP-FPM pools and the full five-layer isolation model regardless of whether they are native or Docker-backed.
If you run into any issues switching Apache MPM or changing PHP versions, post a reply with your OS, the PHP versions involved, and any error output from the panel or logs. We are happy to debug it with you.
The Panelica Team