post_upgrade() {
	if [[ $(vercmp $2 3.0.0-3) -eq -1 ]]; then
		echo '==> The postfix daemon binaries have moved.'
		echo '==> Please restart postfix as soon as possible.'
	elif [[ $(vercmp $2 3.0.1-1) -eq -1 ]]; then
		echo '==> Several Postfix-internal protocols have changed.'
		echo '==> Please restart postfix as soon as possible.'
	fi
}

post_install() {
	getent group postdrop &>/dev/null || groupadd -g 75 postdrop >/dev/null
	getent group postfix  &>/dev/null || groupadd -g 73 postfix  >/dev/null
	getent passwd postfix &>/dev/null || useradd -u 73 -d /var/spool/postfix -g postfix -s /bin/false postfix >/dev/null
	true
}
