How PHP Selector works

On CloudLinux servers, the Select PHP Version tool in cPanel sets the PHP version and the extensions for the account. Each domain can run a different version, which lets an old application keep working while a new one uses a current version.

Choose the version

• Check that your CMS, theme and plugins support the version before you switch.
• Use the newest version that your applications support, and keep a note of the version you chose.
• Test the site after each switch, including the admin area, forms and checkout.

Enable only the extensions you use

Each enabled extension adds code that PHP loads for every request. Turn on the extensions your site needs, such as mysqli, gd, intl and mbstring, and turn off the rest. Opcache should stay on for production sites.

Set sensible limits

Measure before and after

Pick one page that matters, such as the product page or the login page. Measure its response time several times at the same time of day, using a tool such as curl or a load tester, then make one change and measure again. Keep the results in a simple table so you can see what helped.

# Time the response of one page, five times
for i in 1 2 3 4 5; do curl -o /dev/null -s -w "%{time_total}\n" https://example.com/; done

Caching and the database

A page cache removes most PHP work for visitors who are not logged in. Object caches such as Redis help dynamic sites. Database indexes and clean-up help too. See our Redis guide and our database guide.

Keep PHP updated

Security fixes for PHP come in new releases. Move to a supported version when your applications allow it, and read the release notes for the version you choose. Our PHP version support guide lists the supported branches.

Common problems after a change

Application notes

WordPress, Joomla and other CMS platforms publish their supported PHP versions. Check the requirements of the version you plan to use, and test the plugins you depend on, because some older plugins are the last thing to be updated.

Set options per domain, not for the whole server

PHP Selector and MultiPHP settings apply to one domain or account at a time. Use that to keep an old application on its version while a new site runs a current one. Write down which domain uses which version, so the next change is not a guess.

Keep a change log

Record the date, the domain, the old and new PHP version, and the extensions you changed. When a problem appears a week later, the log shows what changed and lets you roll back to the previous setting quickly.

Measure the effect over time

One measurement shows a result for one day. Repeat the same page test each week for a month, at the same time of day, so that a traffic spike or a busy backup does not mislead you. Keep the numbers next to the change log, so each result has a reason.