parse_syncrepl_line: unable to parse "bindmethod=sasl"

I am trying to setup mirror mode configuration setup. Attempted to set bindmethod to sasl and I see following error when slapd starts.

invalid bind config value bindmethod=sasl /home/y/conf/atlas/slapd_ldapmaster.conf: line 62: Error: parse_syncrepl_line: unable to parse "bindmethod=sasl" . failed to add syncinfo slapd destroy: freeing system resources. slapd stopped. connections_destroy: nothing to destroy.

The setups runs fine when bindmethod is set to simple.

Appreciate any info on why this is failing.

--dev