LINE 1: IDENTIFY_SYSTEM error infinitum

Can anyone see why I keep getting the below "IDENTIFY_SYSTEM" error in
my logs when I start my replication database?
I use "postgres primary" as my prefix in the syslog and "postgres
replication" as the replication one.


Jun 30 14:10:25 postgres primary[19617]: [2-1] LOG:  connection
received: host=192.168.2.8 port=55138
Jun 30 14:10:25 postgres primary[19617]: [3-1] LOG:  connection
authorized: user=foobar database=postgres
Jun 30 14:10:25 postgres primary[19617]: [4-1] ERROR:  syntax error at
or near "IDENTIFY_SYSTEM" at character 1
Jun 30 14:10:25 postgres primary[19617]: [4-2] STATEMENT:  IDENTIFY_SYSTEM
Jun 30 14:10:25 postgres replication[19616]: [1-1] FATAL:  could not
receive database system identifier and timeline ID from the primary
server: ERROR:  syntax error at or near "IDENTIFY_SYSTEM"
Jun 30 14:10:25 postgres replication[19616]: [1-2]     LINE 1:
IDENTIFY_SYSTEM
Jun 30 14:10:25 postgres replication[19616]: [1-3]             ^
Jun 30 14:10:25 postgres replication[19616]: [1-4]
Jun 30 14:10:25 postgres primary[19617]: [5-1] LOG:


On primary's postgresql.conf I have this:
port = 5432
wal_level = archive            # minimal, archive, or hot_standby
archive_mode = on
max_wal_senders = 1        # max number of walsender processes
#hot_standby = off


On the replication database's postgresql.conf I have this:
port = 5433
wal_level = minimal
archive_mode = off
#max_wal_senders = 0        # max number of walsender processes
hot_standby = off