Extended PHP Coverage: PHP 5.6 Through 8.5 Now Available
Legacy PHP versions (5.6, 7.0 - 7.4) are now supported alongside native PHP 8.x, powered by isolated Docker runtimes.
Why This Matters
A significant portion of the hosting world is still running applications that cannot move to PHP 8.x. Legacy WordPress installations with unmaintained plugins, Magento 1.x storefronts, older WHMCS module deployments, OSCommerce 2 sites — the list is long, and the economics of rewriting or migrating these applications rarely make sense.
Until now, hosting operators who needed to support these workloads had two options: run a separate, older server with an unmanaged PHP stack, or pay for a commercial OS-level isolation layer. Neither is a good answer.
Panelica now gives you a third path.
12 PHP Versions, One Panel
Panelica supports the following PHP versions:
PHP 8.1 through 8.5 run as native compiled binaries — same as they always have, with per-user PHP-FPM pools and all five isolation layers active. PHP 5.6 through 7.4 run inside Docker containers, isolated at the container boundary.
How It Works — Transparent Shim Architecture
The legacy PHP support is built around what we call a transparent shim. The rest of the panel does not know Docker is involved. From the panel's perspective, PHP 7.4 looks identical to PHP 8.4 — same API, same PHP-FPM interface, same socket path structure.
Here is what that means in practice:
There is no new workflow for end users to learn. Operators see no difference in how they manage domains.
Enabling Legacy PHP Versions
Legacy PHP versions are not installed by default — they are available on demand to keep the base installation lean.
To install a legacy version:
After installation, the version appears immediately in the PHP version selector on the domain edit page. Assign it to a domain, and that site runs on the selected PHP version. Nothing else to configure.
Security Isolation
The same five-layer isolation model that applies to native PHP versions applies here:
For the Docker-backed runtimes, additional container-level hardening is applied: capabilities are dropped, the root filesystem is read-only, network access is restricted to what the site actually needs, and UID mapping aligns with the host user's UID so file ownership remains consistent.
What We Tested
Before shipping this, we ran end-to-end tests across four version transition scenarios:
Broken-window rates (sites that failed to serve a request after transition): 0% for native-to-native, under 5% for transitions involving a Docker runtime during the handoff window.
Distro Compatibility
This works on every OS Panelica supports:
The Docker layer makes the legacy runtime behavior OS-agnostic. What runs on Ubuntu 22 runs identically on AlmaLinux 9 — same container image, same behavior.
Further Reading
We published a detailed technical writeup on the architecture behind this — how the shim works, how Docker and native PHP-FPM coexist on the same socket bus, and how we handle the edge cases. If you want the full picture, it is on our blog at panelica.com/blog.
Share Your Experience
If you are managing legacy applications and have been working around the lack of older PHP support, we would like to hear about it. The Migration HQ category on this forum is a good place to share what you are migrating from, what PHP versions you need, and what you ran into.
Feedback from real deployments helps us make this more robust. If something does not behave as expected, post in the Bug Reports section with the PHP version and OS, and we will take a look.
This announcement applies to all Panelica plans. Docker must be available on the server for legacy PHP runtimes to function. PHP 8.1 through 8.5 native binaries are unaffected by this change and require no Docker.
Legacy PHP versions (5.6, 7.0 - 7.4) are now supported alongside native PHP 8.x, powered by isolated Docker runtimes.
Why This Matters
A significant portion of the hosting world is still running applications that cannot move to PHP 8.x. Legacy WordPress installations with unmaintained plugins, Magento 1.x storefronts, older WHMCS module deployments, OSCommerce 2 sites — the list is long, and the economics of rewriting or migrating these applications rarely make sense.
Until now, hosting operators who needed to support these workloads had two options: run a separate, older server with an unmanaged PHP stack, or pay for a commercial OS-level isolation layer. Neither is a good answer.
Panelica now gives you a third path.
12 PHP Versions, One Panel
Panelica supports the following PHP versions:
- PHP 5.6 — Legacy, Docker runtime
- PHP 7.0 — Legacy, Docker runtime
- PHP 7.1 — Legacy, Docker runtime
- PHP 7.2 — Legacy, Docker runtime
- PHP 7.3 — Legacy, Docker runtime
- PHP 7.4 — Legacy, Docker runtime
- PHP 8.1 — Native binary (end of life, security patches only)
- PHP 8.2 — Native binary, actively supported
- PHP 8.3 — Native binary, actively supported
- PHP 8.4 — Native binary, actively supported
- PHP 8.5 — Native binary, release candidate
PHP 8.1 through 8.5 run as native compiled binaries — same as they always have, with per-user PHP-FPM pools and all five isolation layers active. PHP 5.6 through 7.4 run inside Docker containers, isolated at the container boundary.
How It Works — Transparent Shim Architecture
The legacy PHP support is built around what we call a transparent shim. The rest of the panel does not know Docker is involved. From the panel's perspective, PHP 7.4 looks identical to PHP 8.4 — same API, same PHP-FPM interface, same socket path structure.
Here is what that means in practice:
- Site files remain in the standard location (
home/username/domain.com/public_html) - Databases stay on the server's MySQL instance — no data lives inside a container
- The PHP version dropdown in the domain editor shows all 12 versions, with a (Legacy) badge next to Docker-backed versions
- Users select a version. The panel handles everything else.
There is no new workflow for end users to learn. Operators see no difference in how they manage domains.
Enabling Legacy PHP Versions
Legacy PHP versions are not installed by default — they are available on demand to keep the base installation lean.
To install a legacy version:
- Open Docker Manager in the panel
- Navigate to the PHP Runtimes tab
- Select the version you need (5.6, 7.0, 7.1, 7.2, 7.3, or 7.4)
- Click Install — Panelica pulls the Docker image and configures the runtime automatically
After installation, the version appears immediately in the PHP version selector on the domain edit page. Assign it to a domain, and that site runs on the selected PHP version. Nothing else to configure.
Security Isolation
The same five-layer isolation model that applies to native PHP versions applies here:
- Cgroups v2 — CPU, memory, I/O, and process limits per user, enforced at the kernel level
- Linux namespaces — PID and mount isolation, per-user rootfs (CageFS-style)
- SSH chroot jails — Users cannot see each other's files or processes
- PHP-FPM isolation — Per-user, per-version pools with
open_basediranddisable_functionsenforced - Unix permissions — Dedicated UID/GID per user, home directory set to 700
For the Docker-backed runtimes, additional container-level hardening is applied: capabilities are dropped, the root filesystem is read-only, network access is restricted to what the site actually needs, and UID mapping aligns with the host user's UID so file ownership remains consistent.
What We Tested
Before shipping this, we ran end-to-end tests across four version transition scenarios:
- Native to native (e.g., PHP 8.3 to 8.4) — zero downtime, under 1.5 seconds
- Native to Docker legacy (e.g., PHP 8.3 to 7.4) — transition completes in 3-5 seconds
- Docker legacy to native (e.g., PHP 7.4 to 8.3) — transition completes in 3-5 seconds
- Docker legacy to Docker legacy (e.g., PHP 7.4 to 7.2) — transition completes in 4-5 seconds
Broken-window rates (sites that failed to serve a request after transition): 0% for native-to-native, under 5% for transitions involving a Docker runtime during the handoff window.
Distro Compatibility
This works on every OS Panelica supports:
- Ubuntu 22.04 LTS, 24.04 LTS, 26.04 LTS
- Debian 12 (Bookworm), Debian 13 (Trixie)
- AlmaLinux 9, Rocky Linux 9
The Docker layer makes the legacy runtime behavior OS-agnostic. What runs on Ubuntu 22 runs identically on AlmaLinux 9 — same container image, same behavior.
Further Reading
We published a detailed technical writeup on the architecture behind this — how the shim works, how Docker and native PHP-FPM coexist on the same socket bus, and how we handle the edge cases. If you want the full picture, it is on our blog at panelica.com/blog.
Share Your Experience
If you are managing legacy applications and have been working around the lack of older PHP support, we would like to hear about it. The Migration HQ category on this forum is a good place to share what you are migrating from, what PHP versions you need, and what you ran into.
Feedback from real deployments helps us make this more robust. If something does not behave as expected, post in the Bug Reports section with the PHP version and OS, and we will take a look.
This announcement applies to all Panelica plans. Docker must be available on the server for legacy PHP runtimes to function. PHP 8.1 through 8.5 native binaries are unaffected by this change and require no Docker.