diff -up dovecot-2.2.36/dovecot.service.in.portreserve dovecot-2.2.36/dovecot.service.in
--- dovecot-2.2.36/dovecot.service.in.portreserve	2019-08-13 13:16:17.660982741 +0200
+++ dovecot-2.2.36/dovecot.service.in	2019-08-13 13:16:17.664982728 +0200
@@ -13,6 +13,7 @@ After=local-fs.target network.target net
 [Service]
 Type=forking
 ExecStartPre=/usr/libexec/dovecot/prestartscript
+ExecStartPre=-/usr/sbin/portrelease dovecot
 ExecStart=@sbindir@/dovecot
 PIDFile=@rundir@/master.pid
 ExecReload=@bindir@/doveadm reload