After updating to the new mysql packages to mysql-3.23.24-1 I found that no sql database connection was possible. Investigation proved that the issue is as follows: The mysql-3.23.24-1 sql packages uses a version 10 protocol (mysql protocol) and the original release version uses the version 9 protocol. This results in a protocol mismatch error from mysql when a connection is attempted using apache with the php-4.0.1pl2-9 modules. Resolution: after installing the mysql-3.23.24-1 package and all necessary devel packages, I got the php-4.0.1pl2-9 source package (installation of this package will tell about needed devel packages) and recompiled it with the new mysql libraries installed. The resulting package then had the correct version 10 protocol. After installing the recompiled mod_php and php-mysql packages and restarting the apache server everything went back to normal.
actually, taking that php-4.0.1pl2-9 is broken (see bug 18965), i guess un upgrade to php-4.0.3pl1 would be necessary (linked with the latest mysql package)
The PHP errata we put out yesterday was built using the new MySQL libraries.