Change the PHP version

PHP is the language that runs WordPress and most dynamic websites. Each new version brings more speed and security, but an old plugin may not keep up. From the Upkyo client area, you choose your site's PHP version and its main limits in seconds. This guide explains how to do it, how to pick the right version and what to do if your site shows an error after the change.

Before you start

• Write down the current version so you can return to it.
• Check that your theme and plugins support the target version (each plugin's page on WordPress.org often says so).
• Create a backup if your site matters to your business, see Restore a backup of your website.

Change the PHP version step by step

1. Open your hosting, then PHP.
2. Choose the PHP version.
3. Keep the FPM mode, the fastest one.
4. If needed, adjust the memory limit.
5. If needed, adjust the execution time.
6. If needed, adjust the maximum upload file size.
7. Save: the change is immediate.
8. Open your site and check the main pages.

Which PHP version should you choose?

Choose the most recent version your site supports. Recent versions are faster and receive security fixes. Older versions are no longer patched by the PHP team, so a site running them stays exposed.

If your site is old or uses abandoned plugins, move up one version at a time and test each time. It is the safest way to spot the component causing trouble.

What are the PHP limits for?

• Memory limit (memory_limit): the memory a script may use. Raise it if WordPress shows "Allowed memory size exhausted" or if a page builder freezes.
• Execution time (max_execution_time): the maximum duration of a script. Useful for imports, exports or backups run by a plugin.
• Maximum upload file size (upload_max_filesize): the size of a file uploaded through your site. Raise it if WordPress rejects a theme, a video or a backup to import.

Do not raise these values at random: a very high limit sometimes hides a badly written plugin. Increase them step by step until the problem goes away.

What if the site shows an error after the change?

1. Go back to the previous version in the PHP tool: the site returns to its previous state immediately.
2. Check your hosting error logs (Logs, then Error logs) to see which file is involved.
3. Update the plugin or theme concerned, see Update WordPress, plugins and themes.
4. Try the new version again.

The most common messages are "There has been a critical error on this website", a blank page or a 500 error. In most cases, an outdated plugin is to blame.

Why keep the FPM mode?

FPM mode keeps PHP processes ready to answer requests: pages load faster and the site copes better with traffic spikes. Keep it unless support asks you otherwise. For more speed tips, see Speed up a slow WordPress site.

Frequently asked questions

How do I find out which PHP version my site uses?

Open your hosting, then PHP: the active version is shown there. In WordPress, Tools then Site Health and the Info tab also show it.

Can changing the PHP version break my site?

Yes, if a plugin or the theme is not compatible. The change is reversible: switch back to the previous version and the site works again right away.

How do I increase the WordPress memory limit?

In the PHP tool, raise the memory limit, then save. Reload the page that was causing the problem to check the result.

How do I increase the maximum upload size?

Raise the maximum upload file size in the PHP tool. For a very large file, uploading over SFTP is often simpler, see Connect with FTP or SFTP.

Does the version change take effect immediately?

Yes. As soon as you save, your site uses the new version, with no restart or downtime to plan for.