PHP 5 was released on July 1, 2004, marking a major leap forward in the PHP language with a completely reworked object model, enhanced support for XML and MySQL, and the introduction of key features like exception handling, iterators, and standard PHP Library (SPL). It introduced modern object-oriented programming (OOP) capabilities such as constructors and destructors, private and protected access modifiers, interfaces, abstract classes, and final methods.
Key Features in 5:
Object-Oriented Programming (OOP): Full rework of the object model with proper inheritance, encapsulation, and polymorphism.
Exception Handling: Core support for try-catch blocks, improving error management.
MySQLi Extension: Improved MySQL support with prepared statements, SSL, and object-oriented syntax.
SimpleXML: Streamlined XML parsing and manipulation.
Iterators and SPL: Built-in support for looping through data structures like directories and database results.
End-of-Life (EOL):
All PHP 5 versions reached end-of-life long ago:
PHP 5.6 (last version): EOL on December 31, 2018.
PHP 5.5: EOL on July 10, 2016.
PHP 5.4: EOL on September 3, 2015.
As of 2024, PHP 5 is obsolete and no longer supported. Major platforms like WordPress dropped support in 2023, requiring PHP 7.0 or higher. Using PHP 5 poses serious security risks and is incompatible with modern frameworks and tools.
Current Status:
PHP 5 is not recommended for any new or existing projects.
The latest stable versions are PHP 8.4 (released November 21, 2024) and PHP 8.5 (scheduled for November 20, 2025).
For learning or legacy maintenance, use official documentation at https://www.php.net/manual/php5.php — but only for historical reference.
⚠️ Warning: Running PHP 5 on production servers is unsafe. Upgrade to PHP 8.x for performance, security, and modern language features.
Factsheet
Videos
UPDATE (2024-04-19)
https://github.com/paragonie/sodium_compat/pull/171 -- We've decided to go ahead with a new major version. The original comment is below the line.
We maintain polyfill libraries (random_compat and sodium_compat, which many of you use as a recursive dependency).
Both tentatively support PHP 5.2.4 through the current version (8.4 is coming later this year). This minimum version was specified to ensure our libraries could be used by projects like WordPress.
WordPress requires PHP 7 today.
Does anyone still require support for PHP 5 today? If so, please let us know.
Otherwise, we plan on releasing a new major version for sodium_compat that cuts off support for PHP 5, and sunsetting random_compat (since it's pointless in PHP 7+).
We're aware of Packagist statistics, etc. but that doesn't speak much to the long tail of unpopular projects that haven't made the transfer (esp. if they use an Enterprise OS that backports patches until the heat death of the universe).
We have, previously, explored what a 2.x version of the library may look like. Just using scalar type declarations cut down a lot of the code size.