Choosing the PHP version and changing PHP settings in Plesk Print

Each domain on the server can run its own PHP version with its own settings, so you can update one site without affecting the others.

Changing the PHP version

1. Open Websites & Domains and select the domain.
2. Open Hosting & DNS → Hosting Settings.
3. Select the version you need from the PHP version list.
4. Click OK or Apply.

The change takes effect immediately, so check that the site still works straight afterwards.

Before switching to a newer version, make sure your CMS and its extensions support it. Each major PHP release removes functions that were deprecated earlier, and an out-of-date plugin can bring the site down. Take a backup first, and if the site breaks, switch the version back — the previous versions remain available on the server.

Which version to choose

Use a version that still receives security updates. PHP releases are supported for a limited period, after which they stop receiving fixes altogether — a site left on an unsupported version accumulates known vulnerabilities that will never be patched, whatever else you do to secure it.

In practice this means keeping to one of the two or three most recent versions available in the list, and planning an update rather than waiting for something to force it.

Changing PHP settings

Open Websites & Domains → the domain → PHP Settings. The most commonly adjusted values are:

• memory_limit — how much memory a single script may use. Content management systems with many extensions often need more than the default.
• upload_max_filesize and post_max_size — the maximum size of an upload. Both have to be raised together: an upload is also a POST request, so a large upload_max_filesize alone has no effect.
• max_execution_time — how long a script may run before it is terminated. Relevant for imports and other long-running operations.
• display_errors — leave this off on a live site. Error messages shown to visitors reveal file paths and other details useful to an attacker; use the error log instead.

Settings changed here apply to this domain only. If a value is greyed out, it is fixed at server level and cannot be raised from the subscription — open a ticket if you need it changed.

Checking the result

The PHP version and the settings in force are shown in the panel itself. If your CMS reports different values, check that you have changed the settings for the correct domain, and remember that some applications cache this information.

If the site stops working after a change and switching back does not help, open a ticket from your client area with the domain name and what you changed.