Comment # 11 on bug 978454 from Wolfgang Bauer

The kdebase4-session package has the following postinstall script to cater for
upgrades:

:~> rpm -q --scripts kdebase4-session
postinstall scriptlet (using /bin/sh):
# Reset the DEFAULT_WM value for KDE upgrade compatibility
if [ -f /etc/sysconfig/windowmanager ]; then
    OLD_DEFAULTWM=`grep "DEFAULT_WM" /etc/sysconfig/windowmanager | cut -d '='
-f 2 | cut -d '"' -f 2`
fi

if [ -f /var/adm/fillup-templates/sysconfig.windowmanager ]; then
    TEMPLATE_DEFAULTWM=`grep "DEFAULT_WM"
/var/adm/fillup-templates/sysconfig.windowmanager | cut -d '=' -f 2 | cut -d
'"' -f 2`
fi

# Check the old DEFAULT_WM and whether current DEFAULT_WM exists
if ( [[ $OLD_DEFAULTWM = "startkde4" ]] || [[ $OLD_DEFAULTWM = "startkde" ]] ||
[[ $OLD_DEFAULTWM = "kde4" ]]); then 
    if ( [[ -n $TEMPLATE_DEFAULTWM ]] && [[ $OLD_DEFAULTWM !=
$TEMPLATE_DEFAULTWM ]]); then
        sed -i -e
"s/^DEFAULT_WM=['\"]\?kde.*/DEFAULT_WM=\"${TEMPLATE_DEFAULTWM}\"/g"
/etc/sysconfig/windowmanager
    fi  
fi


We probably should add something similar to plasma5-session...