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Choose the PHP version

3 min read07 November 2026

NeoHeberg web hosting provides PHP 8.4. The real question is not whether that version is recent, but whether your code and its dependencies are compatible with it. A version change is prepared and tested, not discovered in production.

1. The reference version

PHP 8.4 is the version offered on web hosting. It brings performance and syntax improvements, but also deprecations that can break old code. The extensions actually available are listed by phpinfo(). The most common for a PHP site are pdo_mysql, mbstring, curl, gd, intl, zip and opcache; if one is missing, contact support rather than assuming it is installed.

KeyHelp shows the domain's PHP version. If a selector offers several versions, treat 8.4 as the target and the others as temporary transition options.

2. Check the active version

Create a temporary info.php file in the site root:

PHP
<?php
phpinfo();

Open it in a browser, note the version and extensions, then delete it immediately: it exposes the server configuration. On a VPS, php -v and php -m provide the same information from the command line.

3. Know the required extensions

Extension Purpose
pdo_mysql MySQL access
mbstring UTF-8 strings
curl outgoing HTTP calls
gd images and thumbnails
intl localized formats
zip archives and imports
opcache PHP performance

Before changing versions, confirm every extension you use exists. A Call to undefined function at startup often means a missing extension, not an application bug.

4. Test compatibility

The most common deprecations since PHP 8.0 involve dynamic properties, implicit conversions, nullable parameters and some string formats. For a CMS or framework, read the official compatibility matrix and update before switching.

Safe procedure:

  1. Copy the site to a test subdomain.
  2. Enable the target version on that subdomain only.
  3. Walk through pages, forms, uploads and scheduled tasks.
  4. Read the PHP logs: warnings and deprecations predict future errors.
  5. Run automated tests if you have them.

5. Change and verify

If KeyHelp offers a version selector, change it for the domain, save, then clear the application and opcache caches. Test immediately:

  • the home page and a deep page;
  • a database connection;
  • email sending;
  • file uploads.

On regression, revert to the previous version, fix the code, then try again. Do not leave a production site on a version you have not tested, even if it looks fine.

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