--- a/management/univention-ldap/conffiles/etc/ldap/slapd.conf.d/30univention-ldap-server_head	
+++ a/management/univention-ldap/conffiles/etc/ldap/slapd.conf.d/30univention-ldap-server_head	
@@ -24,5 +24,5 @@ sizelimit		@%@ldap/sizelimit@%@
 
 idletimeout		@%@ldap/idletimeout@%@
 
-attributeoptions "entry-"
+attributeoptions "entry-" "lang-"