Understanding Concrete CMS Compatibility: PHP Versions and System Requirements

Concrete CMS, known for its robust and user-friendly content management capabilities, has undergone various updates to remain compatible with evolving server technologies. A critical aspect of maintaining a Concrete CMS website is ensuring that it operates on a server environment that meets its system requirements, particularly the PHP version it supports. This article will provide a detailed overview of Concrete CMS’s compatibility with different PHP versions across its releases and the essential system requirements needed to run it effectively.

Concrete CMS and PHP Version Compatibility:

Concrete CMS has consistently updated its platform to be in sync with the most stable and secure PHP versions available. Here’s a breakdown of the PHP version compatibility for different releases of Concrete CMS:

Concrete CMS Versions 5.6 and Earlier: These versions were compatible with PHP versions up to 5.6. However, as PHP 5.x is no longer supported or receiving security updates, running older versions of Concrete CMS on an outdated PHP version poses significant security risks.

Concrete CMS Versions 5.7 to 8.x: These versions broadened support to PHP 7.0 and above, taking advantage of the improved performance and new features offered by PHP 7.x series. Concrete CMS version 8.5.x is known to support up to PHP 7.3, providing a more efficient and secure environment.

Concrete CMS Version 9.x: The latest in the Concrete CMS family, version 9.x, extends compatibility to PHP 7.4 and PHP 8.0, ensuring the platform benefits from the latest performance optimizations and security enhancements.

System Requirements for Running Concrete CMS:

To ensure the smooth operation of Concrete CMS, your server environment must meet the following system requirements:

PHP Version:
For Concrete CMS versions 8.x and below: PHP 7.2 or higher is recommended.
For Concrete CMS version 9.x: PHP 7.4 or PHP 8.0 is recommended.

PHP Extensions: Several PHP extensions are required, including but not limited to mysqli, gd, dom, and curl. The mbstring extension is also necessary for multibyte string processing.

Database: Concrete CMS supports MySQL version 5.7 or higher, or MariaDB version 10.2.7 or higher, with the InnoDB storage engine.

Web Server: Apache or nginx is recommended, though Concrete CMS can run on any web server that supports PHP and MySQL.

Memory Limit: A PHP memory limit of at least 64MB is recommended, although some intensive operations may require more.

Post Max Size and Upload Max Filesize: These settings in the php.ini file should be large enough to handle the biggest file you expect to upload, with post max size typically larger than upload max filesize.

Best Practices for Concrete CMS Hosting:

When hosting a Concrete CMS website, it’s best to:

Always use the latest PHP version that is officially supported by your version of Concrete CMS for security and performance reasons.

Regularly update your Concrete CMS installation to the latest release within your version branch.

Stay informed about PHP’s own end-of-life schedule and plan upgrades accordingly.

Utilize hosting environments optimized for Concrete CMS, with support for command line access, task scheduling (cron jobs), and backups.


Concrete CMS’s compatibility with different PHP versions highlights its commitment to security and performance. By adhering to the outlined system requirements, web developers and site owners can leverage the full potential of Concrete CMS to manage and deliver content effectively. Always consult the official Concrete CMS documentation or your hosting provider for the most current system requirements and PHP compatibility information to ensure your CMS runs optimally.