As you may know MySQL ® announced 5.0.91 and 5.1.47 with serious security fixes, so we provide binary releases of Percona Server 5.0 and Percona Server / XtraDB 5.1 with security patches.
Release Percona Server 5.0.91-rel22 is available in our download area:
Release Percona Server/XtraDB 5.1.45-rel10.2 is available also ( we backported patches from 5.1.47 to 5.1.45):
Updated RPM and DEB are also available in our repositories.
We know that there still are many active MySQL 4.0 and MySQL 4.1 installations and we understand how hard it is upgrade 4.0/4.1 to 5.1. With published exploits these installation are now under serious risks. If you are interested in backporting patches to 4.0 / 4.1 or to older 5.0 and 5.1 releases, it is available under Percona Maintenance package or regular Consulting