openldap 2.3.35 (server and client)

I'm trying to use the postread control together with the modify+increment extension. mod+inc works, but I get nothing back with the ldapmodify(1) command.

Network sniffing shows that the server is indeed returning the new value: seems just that ldapmodify(1) is not displaying it.

$ ldapmodify -x -D cn=admin,dc=example,dc=com -w pass -e postread=uidNumber << EOF dn: cn=unixidpool,dc=example,dc=com changetype: modify increment: uidNumber uidNumber: 1

EOF modifying entry "cn=unixidpool,dc=example,dc=com"

uidNumber was incremented, so that part worked.

Am I not using ldapmodify(1) correctly or is this a missing feature in that command?