What are the differences between PHP3 and PHP4 and PHP5 ?

[hoangvu]

I'm a new to the PHP thing. I want to try to setup my server to handle PHP3 and PHP4 requests easily. e.g. I have some scripts that are PHP3 and want to start learning PHP4. Instead of doing the simple (like anything I do is simple URL ) thing, I am attempting to set up apache to support MySQL, PHP3, PHP4, SSL, ColdFusion, SteelBlue, and maybe even Frontpage.

 

[shophia]

PHP3 is oldest constant version and it was clean technical language constructive like C.

Where as PHP4 have certain OOPs theory added such as class and object with new functionality.

PHP5 around every major oops functionality has been added along with below thing :

1) Implementation of exclusions and exception handling
2) Type suggesting which permits you to force the type of a exact argument

 

[tayloralina]

PHP3 stable is the older version was purely procedural language constructive such as C. Where PHP4 and some concept of amnesty and added such class object with a new job.

 

[amitbhureem30]

(PHP3 stable is the older version was purely procedural language constructive such as C. Where PHP4 and some concept of amnesty and added such class object with a new job.)


thank for sharing

 

[Unknown]

Well, there are many differences between these three PHP's.

PHP3- is the oldest one out of the three. Nobody is really using it anymore, neither should you.
PHP4- second oldest, improved from the PHP3 but still ''worse'' than PHP5 which you should be using.
PHP5- has the most of the OOP functionality, best performance, most functional overall and is the one you should strive to use.

If you want a really detailed list, I think that they have one in the manual on the php.net website hope that this was a bit helpful!

 

[Nemanja]

Nemanja

I agree with this opinion but at this time, I would suggest you forget these PHP version and upgrade to PHp 7
because my sites are using PHP 7 and they have better performance when using this version.

 

[jason223]

PHP is a server-side scripting language that is used in website development. PHP4 and PHP5 are two different versions of PHP. PHP4 was first released in May of 2000. PHP5 was later released in 2004 and came powered by the Zend Engine II that is considered by the development community as an improvement over PHP4.

After various versions of PHP4, the last version titled PHP4.4.9 released in August of 2008. After the last release, it was announced that PHP4 would not longer be developed, including future security updates for the language.

With the lack of support for PHP4, many new servers are no longer supporting php4 and developers are having to make changes to their websites to support PHP5 instead of PHP4.

 

[Mike001]

I was very surprised reading through all the comments and not one person mentioned the biggest and most important reason for working with the latest versions of most any software language....SECURITY.....

Do not deploy with PHP versions 3 or 4. There are far too many security issues and they no longer have support in the PHP community. You will also limit yourself in what you can accomplish with those two older languages.

I have included a high level overview of some of the major changes that occurred in the development of PHP. This is by no way a complete list as that would take days to put together, there have been 10's of thousands of changes to the language just over the last five or six years.


PHP3 - (No Longer Supported) Oct. 2000, was a good server side language that gave us web developers an opportunity to work with the server side of our applications, this was one of the first languages available to web developers that allowed this, at that time the web was very new and static web pages were the norm. Originally develop as a Personal Home Page language, Rasmus Lerdorf in 1994, he developed the language for his personal use, it worked but had many areas that needed to be developed. There was only one version of PHP3 it was quickly replaced by PHP4 in just a few short months.

PHP4 - (No Longer Supported) developed and released in May 2001 was a vast improvement to PHP3. Initial types of security was implemented and support of Arrays was added this was a large step forward. Version 4 went through many updates over the years and major upgrades to the language were occurring approximately every 3 months, the PHP group began to grow and the development was very instrumental in the changes that were occurring and the implementation of database support. As popularity grew there were still many issues discovered with the security implementation of the langauge across larger sites. Version 4 was the first version that supported the Apache server configuration, as that was becoming the most popular web server being deployed. Many security issues and numerous language updates occurred throughout the life-cycle of PHP4. The first real SQL middle-ware was developed during version 4 and full support for remote databases was established.

PHP5 - released in July 2004 this was a major upgrade to PHP. Still under active support. Supported much better error handling, completely rewritten UNIX and Windows handlers, for better speed and security updates. Support for XML files was added in a early version of PHP5 and became very popular as data structure format. Support for SSL was added. Meta tag support was added as SEO became much more important as the web began to grow. Major security issues were addressed with additional support for hashing and the beginnings of the SALT functionality was being added to the language. Throughout the course of the Version 5 development thousands of bugs were addressed and fixed, security were constantly being identified and addressed and speed and 64 bit support were addressed and added. Extensions were added to the language to allow for connections to multiple database architectures and MySQL soon became the most popular database for the web. This still holds true even today although there are new database architectures that are catching up. MD5 encryption scheme was developed and added to PHP5. The popularity of OOP started to drive the development of PHP in a more class based language. As their popularity increased support for JavaScript, jQuery and JSON were added to the language. Version 5 eventually split into 2 separate branches of development, one branch staying in the procedural mode of development and the other working towards a class branch development. The last major update to PHP Version 5 occurred in July of 2017. There are well over 100 versions of PHP5 addressing enhancement to the language and fixing bugs that have been identified.

PHP6 - never officially released and development scrapped in June 2014.

PHP7 - Released Dec. 2015. Speed and multi-thread asynchronous support was the major driving factor. Numerous security updates and encryption updates added to the initial release. Growing in popularity but still way behind PHP5 in deployments.

I hope this helps.