PHP Version Selectors
What a PHP Version Selector Does
A cPanel PHP version setting lets you choose which release of PHP runs each site on an account. PHP is the programming language behind many content management systems, forums and shopping carts. The selector is the panel tool that assigns a version to a domain or folder.
A server can run several PHP versions side by side. This matters because applications have different needs. An older application may need an older release, while a newer one may need a current release. Per-site selection gives each application the environment it was built for.
Supported versions receive security fixes, while versions past their end of support do not. Running an unsupported version is therefore a security concern, and keeping sites on supported versions is the goal.
Handlers, Limits and Extensions
The handler is the method the web server uses to pass PHP work to the PHP engine. PHP-FPM, a process manager, runs PHP in separate pools of worker processes, often one pool per account, which isolates sites from each other. It is a common choice on current panels, and older handlers still appear on some servers.
Panels also expose per-site settings such as memory limit, maximum execution time, upload size and input variable limits. Raising a limit can fix a failed upload, but it also lets a single script use more memory, so values should match what the application actually needs.
Extensions add functions such as image handling or database drivers, and they are often switched on or off in the same area. Which versions a server offers can depend on its operating system, as covered in control panel OS compatibility.
Frequently asked questions
Can I run different PHP versions on different sites?
Yes, if the panel supports per-site selection. Each domain or folder can then run its own version, so an older application can keep working while a newer one uses a current release. Because the setting applies only to the folder or domain selected, check that each site uses the version you intended.
Why does my site break after changing the PHP version?
The new version may have removed a function the application uses, a plugin may not yet support it, or a required extension may be disabled. Some errors appear only on certain pages, so test the whole site rather than just the home page. An application installed through a one-click installer is affected by the same choice, as described in one-click installers.