Seven years ago, was released the latest version in the PHP4 branch : 4.4.9. Today the latest versions in the official PHP.net website are 5.4.40, 5.5.24, and 5.6.8. While most of the community are waiting for the latest PHP 7, many others did not upgrade yet their installations from PHP 5.3 which end of life announced since last year, or PHP 5.2.
PHP 5.4 and 5.5 branch EOL are respectively 2015 and 2016. So if you are not in a hurry you should start coding with PHP 7, or migrate your existing code to PHP 7! If you prefer PHP 5.6 or 5.5 you will have one year or two before you will be obliged to migrate. That’s too short and very annoying for large projects but there still enough time to get all this planned.
So make sure you read carefully migration guides for 5.5 and 5.6, especially the deprecated features and the backward incompatible changes. But if you have a very old code that you need to run even locally, guess it’s not that hard to do !
For example, the screenshots above is a the seven years old 4.4.9 compiled recently with Apache 2.4, MySQL NDB cluster 6.3 and Oracle 10.2, among many others. That’s not recommended at all, but that’s the power of Open Source, and the power of PHP.
Remember this in 2022 !