How to Upgrade PHP4 to PHP5 in One Click

We upgraded our server from PHP4 to PHP5 today. Irritated by my internal server errors, I checked the PHP version of the wordpress hosting server and realized our blog was still hosted on the very old PHP4.4.9 version, though PHP5.2.9 version is the latest version available. So how to upgrade PHP4 to PHP5?

PHP4 is Obsolete, Get PHP5

A quick look at the PHP5 changelog will convince you that a lot has changed and PHP5 promises to be much faster, stable and secure than PHP4. Though PHP 5 offers many new features, it continues to be very compatible with earlier versions of PHP with little functionality being broken in the process.

Even the PHP official site notifies that support for PHP 4 has been discontinued since 31 Dec 2007 and they recommend� everyone to upgrade to PHP 5.2, but I could not figure out a what to do after downloading PHP5.2. When I looked about for ways to upgrade PHP4 to PHP5, I found that it seems too technical and complicated for a blogger to perform without professional technical support.

I checked our Dreamhost hosting had announced in August 2008 that

Since PHP4 has been officially discontinued, we�re taking our first steps in discontinuing our own support. If you currently have any domains using PHP4 (in either mod_php or CGI mode), they�ll continue to work for the foreseeable future. The only change occurring is that you will no longer be able to set up a new domain as PHP4 or convert an existing PHP5 domain to use PHP4.

The few remaining one-click packages we had that required PHP4 are being upgraded simultaneously so that we�ll have no one-click packages that won�t work with new domains. If you�re in a position to do so, this might be a good time to start working on getting your websites working with PHP5 so that the later transition is easier. In most cases, the switch should be trivial.

Obviously our server had not been upgraded by default and PHP4 continued to serve us well. But the persistent internal server errors prompted us to probe deeper. I checked that the WordPress minimum requirements are still PHP version 4.3 or greater, so we were scraping the minimum requirement with PHP4.4

Upgrade PHP4 to PHP5 Easily

In my experience Dreamhost panel usually makes non-technical webmasters perform a lot of powerful stuff in a few easy clicks, so I looked around for this option… and actually found it after a lot of browsing. Dreamhost users can find the options at Domains > Manage Domains > Edit Domain

There was a drop-down option to choose your PHP version – I simply selected PHP5.2.x and got a message

And actually after 5 minutes when I checked our PHP version, it was upgraded to PHP5.2.6! Now that was fast and simple.

If you are on Dreamhost, you can also check and upgrade your PHP version. But remember you cannot switch back to PHP4 after switching to PHP5 as the option disappears from the panel after upgrade. If anything breaks, you are doing this at your own risk.