WordPress › PHP 4 and MySQL 4 End of Life Announcement:
For WordPress 3.2, due in the first half of 2011, we will be raising the minimum required PHP version to 5.2.
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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.
Давно пора было уже.
Полагаю, что количество кода должно сократиться в полтора раза, минимум.