# PHP Version Required to Run the MatthiasMullie Minify Library in OpenMage

> Discover the PHP version required for the MatthiasMullie Minify library in OpenMage. Learn the minimum PHP 5.3.0 requirement to ensure compatibility.

- Repository: [Fabrizio Balliano/openmage-cssjs-minify](https://github.com/fballiano/openmage-cssjs-minify)
- Tags: how-to-guide
- Published: 2026-03-01

---

**The MatthiasMullie Minify library requires PHP 5.3.0 or higher to run, as specified in the [`composer.json`](https://github.com/fballiano/openmage-cssjs-minify/blob/main/composer.json) configuration of both the library itself and the fballiano/openmage-cssjs-minify module.**

The fballiano/openmage-cssjs-minify module integrates the MatthiasMullie Minify library into OpenMage (Magento) environments to optimize CSS and JavaScript assets. Understanding the PHP version requirements ensures compatibility and prevents runtime errors during the minification process.

## PHP Version Constraint: 5.3.0 Minimum

The MatthiasMullie Minify library explicitly requires **PHP 5.3.0 or higher**. This constraint appears in the `require` section of the library's [`composer.json`](https://github.com/fballiano/openmage-cssjs-minify/blob/main/composer.json) file as `"php": ">=5.3.0"`. This version requirement ensures access to **namespaces** and **late static binding**, which are PHP 5.3 features utilized within the minification classes.

## Where the PHP Version Requirement is Defined

### Module composer.json

In the fballiano/openmage-cssjs-minify repository, the root [[`composer.json`](https://github.com/fballiano/openmage-cssjs-minify/blob/main/composer.json)](https://github.com/fballiano/openmage-cssjs-minify/blob/main/composer.json) declares the PHP constraint that propagates to dependencies. This file ensures that the environment meets the minimum requirements before installing the MatthiasMullie Minify library via Composer.

### Library composer.json

The upstream [`matthiasmullie/minify`](https://github.com/matthiasmullie/minify/blob/master/composer.json) repository explicitly defines the PHP version requirement in its own [`composer.json`](https://github.com/fballiano/openmage-cssjs-minify/blob/main/composer.json):

```json
"require": {
    "php": ">=5.3.0",
    ...
}

```

## Practical Implementation in OpenMage

The module implements the library within the OpenMage framework through the `Fballiano_CssjsMinify_Model_Observer` class. Located at [[`app/code/community/Fballiano/CssjsMinify/Model/Observer.php`](https://github.com/fballiano/openmage-cssjs-minify/blob/main/app/code/community/Fballiano/CssjsMinify/Model/Observer.php)](https://github.com/fballiano/openmage-cssjs-minify/blob/main/app/code/community/Fballiano/CssjsMinify/Model/Observer.php), this observer instantiates the minification classes during the layout generation process.

### Basic Usage Example

When the library is properly loaded via Composer autoloading, you can minify assets as follows:

```php
<?php
use MatthiasMullie\Minify;

// Minify CSS files
$cssMinifier = new Minify\CSS('/path/to/source.css');
$cssMinifier->minify('/path/to/result.min.css');

// Minify JavaScript files
$jsMinifier = new Minify\JS('/path/to/source.js');
$jsMinifier->minify('/path/to/result.min.js');

```

### Combining Multiple Files

The library supports combining multiple source files into a single minified output:

```php
<?php
require_once 'vendor/autoload.php';
use MatthiasMullie\Minify;

$css = new Minify\CSS();
$css->add('/css/file1.css');
$css->add('/css/file2.css');
$css->minify('/css/combined.min.css');

```

These operations require PHP 5.3.0 or higher to support the namespace and class structure utilized by the MatthiasMullie Minify library.

## Summary

- The MatthiasMullie Minify library requires **PHP 5.3.0 or higher** to function correctly.
- The version constraint is defined in both the library's [`composer.json`](https://github.com/fballiano/openmage-cssjs-minify/blob/main/composer.json) and the fballiano/openmage-cssjs-minify module's [`composer.json`](https://github.com/fballiano/openmage-cssjs-minify/blob/main/composer.json).
- The library utilizes PHP 5.3 features such as **namespaces** and **late static binding**.
- Implementation within OpenMage occurs through the `Fballiano_CssjsMinify_Model_Observer` class located at [`app/code/community/Fballiano/CssjsMinify/Model/Observer.php`](https://github.com/fballiano/openmage-cssjs-minify/blob/main/app/code/community/Fballiano/CssjsMinify/Model/Observer.php).

## Frequently Asked Questions

### What is the minimum PHP version required for the MatthiasMullie Minify library?

The minimum PHP version required is **5.3.0**. This requirement is explicitly stated in the library's [`composer.json`](https://github.com/fballiano/openmage-cssjs-minify/blob/main/composer.json) file under the `require` section as `"php": ">=5.3.0"`. Both the upstream library and the fballiano/openmage-cssjs-minify module enforce this constraint to ensure compatibility with modern object-oriented PHP features.

### Can I use the MatthiasMullie Minify library with PHP 8.x?

Yes, the library is fully compatible with PHP 8.x versions. The `>=5.3.0` constraint in [`composer.json`](https://github.com/fballiano/openmage-cssjs-minify/blob/main/composer.json) allows for any PHP version equal to or greater than 5.3.0, which includes modern PHP 8.0, 8.1, 8.2, and 8.3 releases. The library maintains backward compatibility while supporting modern PHP environments.

### Where is the PHP version requirement defined in the OpenMage module?

The requirement is defined in the root [`composer.json`](https://github.com/fballiano/openmage-cssjs-minify/blob/main/composer.json) file of the fballiano/openmage-cssjs-minify repository. Additionally, the actual constraint originates from the dependency package `matthiasmullie/minify`, which declares `"php": ">=5.3.0"` in its own [`composer.json`](https://github.com/fballiano/openmage-cssjs-minify/blob/main/composer.json) file. Composer validates both constraints during installation.

### What PHP 5.3 features does the MatthiasMullie Minify library utilize?

The library utilizes **namespaces** (introduced in PHP 5.3) to organize its classes under the `MatthiasMullie\Minify` namespace. It also relies on **late static binding** and other object-oriented improvements introduced in PHP 5.3 to handle minification logic for CSS and JavaScript files efficiently.