PHP code may be executed with a command line interface (CLI), embedded into HTML code, or it can be used in combination with various web template systems, web content management systems, and web frameworks. PHP code is usually processed by a PHP interpreter implemented as a module in a web server or as a Common Gateway Interface (CGI) executable. The web server combines the results of the interpreted and executed PHP code, which may be any type of data, including images, with the generated web page. PHP can be used for many programming tasks outside of the web context, such as standalone graphical applications and robotic drone control.
The standard PHP interpreter, powered by the Zend Engine, is free software released under the PHP License. PHP has been widely ported and can be deployed on most web servers on almost every operating system and platform, free of charge. The PHP language evolved without a written formal specification or standard until 2014, with the original implementation acting as the de facto standard which other implementations aimed to follow. Since 2014, work has gone on to create a formal PHP specification.
What is the relation between the versions?
PHP/FI 2.0 is an early and no longer supported version of PHP. PHP 3 is the successor to PHP/FI 2.0 and is a lot nicer. PHP 7 is the current generation of PHP, which uses the Zend engine 3 which, among other things, offers many additional OOP features. Can I run several versions of PHP at the same time? Yes. See the INSTALL file that is included in the PHP source distribution.
I think I found a bug! Who should I tell?
You should go to the PHP Bug Database and make sure the bug isn't a known bug. If you don't see it in the database, use the reporting form to report the bug. It is important to use the bug database instead of just sending an email to one of the mailing lists because the bug will have a tracking number assigned and it will then be possible for you to go back later and check on the status of the bug. The bug database can be found at » https://bugs.php.net/. add a note add a note.