Title: PHP version: 3 vs 4.2
Last modified: August 18, 2016

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# PHP version: 3 vs 4.2

 *  [nicknormal](https://wordpress.org/support/users/nicknormal/)
 * (@nicknormal)
 * [20 years, 2 months ago](https://wordpress.org/support/topic/php-version-3-vs-42/)
 * question: what will happen if WP 2.0.1 is installed on a server using version
   3.x of PHP? are there functions that absolutely will not work??
 * we’re using v3 because v4 conflicts with this database script we use for our 
   website, and was coded years ago by someone who no longer works for us and we
   can’t afford a private developer to upgrade the script to v4. we want to install
   WP 2.0.1 but i want to get a heads up on what won’t work.
 * anyone know?
 * cheers
    nick_normal

Viewing 4 replies - 1 through 4 (of 4 total)

 *  [Kafkaesqui](https://wordpress.org/support/users/kafkaesqui/)
 * (@kafkaesqui)
 * [20 years, 2 months ago](https://wordpress.org/support/topic/php-version-3-vs-42/#post-353497)
 * There are a number of PHP 4 functions WordPress makes use of which are not in
   PHP 3. So it most likely will not work for you.
 *  Thread Starter [nicknormal](https://wordpress.org/support/users/nicknormal/)
 * (@nicknormal)
 * [20 years, 2 months ago](https://wordpress.org/support/topic/php-version-3-vs-42/#post-353705)
 * any hard evidence? anyone? or know of a link to an update log with specifics.
   i can’t find one.
 *  [Kafkaesqui](https://wordpress.org/support/users/kafkaesqui/)
 * (@kafkaesqui)
 * [20 years, 2 months ago](https://wordpress.org/support/topic/php-version-3-vs-42/#post-353707)
 * Update log of what? Of PHP4? You can dig up such on [php.net](http://php.net).
 * WordPress has been a PHP4 application from the start. b2, the precursor to WordPress,
   was PHP4-only as well. The requirements doc pretty much spells out what is needed
   to run WordPress:
 * [http://wordpress.org/about/requirements/](http://wordpress.org/about/requirements/)
 * But you’re more than free to install it and see if it works for you.
 *  Thread Starter [nicknormal](https://wordpress.org/support/users/nicknormal/)
 * (@nicknormal)
 * [20 years, 2 months ago](https://wordpress.org/support/topic/php-version-3-vs-42/#post-353736)
 * i was asking more for specifics as to what in WP _won’t work_ ; i.e. will we 
   not be able to add multiple authors for some reason? will we not be able to create
   category parents? obviously there are reasons why it says 4.2, not 3.x, and i’m
   looking for specifics, which aren’t listed anywhere, curious if a PHP developer
   could spot the gaps. but to no avail.
 * cheers

Viewing 4 replies - 1 through 4 (of 4 total)

The topic ‘PHP version: 3 vs 4.2’ is closed to new replies.

## Tags

 * [php](https://wordpress.org/support/topic-tag/php/)

 * In: [Installing WordPress](https://wordpress.org/support/forum/installation/)
 * 4 replies
 * 2 participants
 * Last reply from: [nicknormal](https://wordpress.org/support/users/nicknormal/)
 * Last activity: [20 years, 2 months ago](https://wordpress.org/support/topic/php-version-3-vs-42/#post-353736)
 * Status: not resolved

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