Earlier this week, the PHP team released PHP 4.4.8. Baring any major security holes between now and August 8th, it will be the last release of PHP 4. Ever.
We are also one month away from the GoPHP5 deadline, after which any new releases of almost every major PHP project will require at least PHP 5.2. If you or your web host is running an older version, you are going to run into problems.
The future is neigh. Is your server ready?