SymptomsAfter upgrade from Parallels Plesk Panel 9.0.0 update1 (release) to Parallels Plesk Panel 9.0.0 update2 (package psa-hotfix4-9.0.0) mail message headers have incorrect structure.
Package psa-mail-driver-common is not upgraded and so the old version of binary file $PRODUCT_ROOT_D/handlers/hooks/spf is used for messages processing.
ResolutionYou should upgrade package psa-mail-driver-common manually to resolve the problem.
Package for Parallels Plesk Panel 9.0.0 update 2 is psa-mail-driver-common-9.0.0-OS.build90081222.11. The packages is located in /opt/maildrivers of Parallels Plesk Panel 9.0.0 distributive.
You may download the package appropriate for your operating system and architecture from the autoinstaller website http://autoinstall.plesk.com/.
For example for CentOS 5, 32-bin the package is located in http://autoinstall.plesk.com/PSA_9.0.0/dist-rpm-CentOS-5-i386/opt/maildrivers/
Download the package and install it with rpm -Uvh (for RedHat family) or with deb -i (for Debian and Ubuntu).