WordPress has announced this with its latest release of their new version WordPress 3.0.1 that WordPress 3.1 would be last version which is scheduled to be release by late 2010 which support PHP 4 and My SQL 4.

WordPress 3.2 which will ready by beginning of first half of 2011 will no longer support the PHP 4 and My SQL 4.This means that your web host need to have PHP version of 5.2, because that’s what the vast majority of WordPress users are using, and it offers substantial improvements over earlier PHP 5 releases.

As reported by WordPress: The numbers are now, finally, strongly in favour of this move. Only around 11 percent of WordPress installs are running on a PHP version below 5.2. Many of them are on hosts who support PHP 5.2 — users merely need to change a setting in their hosting control panel to activate it. We believe that percentage will only go down over the rest of the year as hosting providers realize that to support the newest versions of WordPress (or Drupal, or Joomla), they’re going to have to pull the trigger.

In less exciting news, we are also going to be dropping support for MySQL 4 after WordPress 3.1. Fewer than 6 percent of WordPress users are running MySQL 4. The new required MySQL version for WordPress 3.2 will be 5.0.15.

So fellow hosters gearup for the change and if you don’t have contact your host  for that.

Good luck.