PHP 7.3 End-of-life (EOL) in December 2021

As of December 6, 2021, PHP 7.3 will no longer be supported by the PHP community. That’s why you should upgrade to a newer version now. Anyone running PHP 7.3 on their server after the ‘end-of-life’ date will not be protected against new security vul­ner­ab­il­it­ies. In the worst case this could lead to suddenly in­ac­cess­ible websites or even data theft. In this article, we explain how PHP 7.3 fits in with past and sub­sequent versions and how to proceed with upgrading.

Alongside Python and JavaS­cript, PHP is one of the most popular server-side web pro­gram­ming languages. Popular web platforms such as content man­age­ment systems WordPress, Joomla! and TYPO3 are built on the language. MediaWiki - the software that powers Wikipedia, the online learning platform Moodle and many other well-known and popular web-based systems are also written in PHP.

Even though the scripting language used to have a somewhat dubious repu­ta­tion among de­velopers, the PHP basics are easy to learn. Building a website in PHP is quite fun. You learn a lot about how the ubi­quit­ous client-server ap­plic­a­tions work and what a website is made of.

The current PHP 8 version extends per­form­ance im­prove­ments using the modern approach of ‘Just-in-time com­pil­a­tion’ (JIT). JIT also forms the basis of other scripting languages such as Python. However, per­form­ance im­prove­ments aren’t as drastic as the change from PHP 5.6 to PHP 7.

Being an open-source project, PHP is developed by a community of volunteer pro­gram­mers. Large companies con­trib­ute their share; Facebook, for example, has his­tor­ic­ally con­trib­uted a great deal to the de­vel­op­ment of the language. New versions are developed and released regularly. Every year, around the beginning of December, a new PHP version is released.

Each new release of PHP is actively developed for two years and regularly updated during this time. Sub­sequently, the version receives security updates for another 12 months. This ensures that newly dis­covered security vul­ner­ab­il­it­ies are not im­me­di­ately exploited to cripple sites and steal data. At the same time, ad­min­is­trat­ors are given plenty of time to prepare their systems for the move to a new PHP version.

PHP version 7.3 was released at the end of 2018. Three years on, PHP 7.3 is at the end of its life (‘End-of-life’, EOL). As of December 6, 2021, no further security updates will be issued for PHP 7.3. Site operators should switch to PHP 7.4 or 8.x.

The table gives an overview of the versions released thus far and their EOL dates, beginning with PHP 7.3:

PHP forms part of almost every web hosting package. Every provider has their own process for upgrading the PHP in­stall­a­tion. Generally, changing the PHP version on the server is possible. However, this can lead to dis­rup­tions in the hosted PHP software. Therefore, it’s best to try an upgrade on a staging server.

In general, most software running on PHP 7.3 is com­pat­ible with PHP 7.4 or 8.x. However, it’s important to ensure that the software is up to date. Consider WordPress which requires version 5.3 as a basis for com­pat­ib­il­ity with PHP 7.4.

If a PHP software was installed using package manager Composer, you can easily verify whether the software will survive a version swap. To do this, use the Composer command with the --dry-run option, which simulates changes. After logging in via SSH and changing to the root directory of the PHP project, we execute the following commands in suc­ces­sion:

1. Configure Composer to current PHP version (8.0.12 at the time of writing):

2. Check whether the latest versions of the de­pend­en­cies support the specified PHP version:

3. Verify that the current versions of the de­pend­en­cies support the specified PHP version: