Downgrade php without breaking plesk
I ussualy do this:
# yum remove php*
(plesk gets broken but no problem)
I download plesk autoinstaller from parallels.com and install it again, in the installation i select php and php5.1.6 installs.
All the configuration and data in Plesk is OK...
I have the same problem when I try to upgrade. I's a Plesk BUG!!!
I hope they solve it soon, my apache stops suddenly when I change some configuration in a domain in plesk.