pre_upgrade() {
    mv /etc/lighttpd/lighttpd.conf  /etc/lighttpd/lighttpd.conf.old
}
post_upgrade() {
    sed -i 's|"^/mythweb|"/{1,2}mythweb|g' /etc/lighttpd/lighttpd.conf
    touch /etc/lighttpd/lighttpd.user
}