post_install() {
    usr/sbin/update-libguestfs-appliance
}

remove_old_appliance() {
    rm -f usr/lib/guestfs/{kernel,initrd,root,README.fixed}
}

pre_remove() {
    remove_old_appliance
    rm -f /var/cache/guestfs/appliance-*
}

pre_upgrade() {
    remove_old_appliance
}

post_upgrade() {
    post_install
}