diff --git a/target/postfix/main.cf b/target/postfix/main.cf
index 48a53d76..1ce6b261 100644
--- a/target/postfix/main.cf
+++ b/target/postfix/main.cf
@@ -56,14 +56,14 @@ disable_vrfy_command = yes
 # Postscreen settings to drop zombies/open relays/spam early
 postscreen_dnsbl_action = enforce
 postscreen_dnsbl_sites = zen.spamhaus.org*3
-	bl.mailspike.net
-	b.barracudacentral.org*2
-	bl.spameatingmonkey.net
-	dnsbl.sorbs.net
-	psbl.surriel.com
-	list.dnswl.org=127.0.[0..255].0*-2
-	list.dnswl.org=127.0.[0..255].1*-3
-	list.dnswl.org=127.0.[0..255].[2..3]*-4
+    bl.mailspike.net
+    b.barracudacentral.org*2
+    bl.spameatingmonkey.net
+    dnsbl.sorbs.net
+    psbl.surriel.com
+    list.dnswl.org=127.0.[0..255].0*-2
+    list.dnswl.org=127.0.[0..255].1*-3
+    list.dnswl.org=127.0.[0..255].[2..3]*-4
 postscreen_dnsbl_threshold = 3
 postscreen_dnsbl_whitelist_threshold = -1
 postscreen_greet_action = enforce
@@ -101,5 +101,14 @@ policyd-spf_time_limit = 3600
 # Header checks for content inspection on receiving
 header_checks = pcre:/etc/postfix/maps/header_checks.pcre
 
-# Remove unwanted headers that reveail our privacy
+# Remove unwanted headers that reveal our privacy
 smtp_header_checks = pcre:/etc/postfix/maps/sender_header_filter.pcre
+
+# The default compatibility_level is 0 - which retains legacy settings defaults:
+# http://www.postfix.org/COMPATIBILITY_README.html
+# If backwards-compaitibilty log messages appear, fix them by explicitly adding
+# the legacy or new default value (alternatively raise the compatibility_level)
+#
+# TODO: The next compatibility_level is 3.6, when Postfix 3.6 is available consider
+# bumping this value after taking the compaitibilty changes into account.
+compatibility_level = 2
diff --git a/target/postfix/master.cf b/target/postfix/master.cf
index 747a8bef..4369f276 100644
--- a/target/postfix/master.cf
+++ b/target/postfix/master.cf
@@ -67,7 +67,7 @@ lmtp      unix  -       -       n       -       -       lmtp
 anvil     unix  -       -       y       -       1       anvil
 scache    unix  -       -       y       -       1       scache
 
-sender-cleanup unix n   -       -       -       0       cleanup
+sender-cleanup unix n   -       n       -       0       cleanup
   -o syslog_name=postfix/sender-cleanup
   -o header_checks=pcre:/etc/postfix/maps/sender_header_filter.pcre
 
diff --git a/target/scripts/startup/setup-stack.sh b/target/scripts/startup/setup-stack.sh
index 63843f4b..0d8293f5 100644
--- a/target/scripts/startup/setup-stack.sh
+++ b/target/scripts/startup/setup-stack.sh
@@ -762,9 +762,6 @@ function _setup_postfix_override_configuration
   else
     _log 'trace' "No extra Postfix settings loaded because optional '/tmp/docker-mailserver/postfix-master.cf' was not provided"
   fi
-
-  _log 'trace' "Set Postfix's compatibility level to 2"
-  postconf compatibility_level=2
 }
 
 function _setup_postfix_sasl_password
diff --git a/test/tests.bats b/test/tests.bats
index 453ae85f..5ace6b09 100644
--- a/test/tests.bats
+++ b/test/tests.bats
@@ -510,7 +510,7 @@ EOF
   assert_failure
   run docker exec mail grep -i '(!)connect' /var/log/mail/mail.log
   assert_failure
-  run docker exec mail grep -i 'backwards-compatible default setting chroot=y' /var/log/mail/mail.log
+  run docker exec mail grep -i 'using backwards-compatible default setting' /var/log/mail/mail.log
   assert_failure
   run docker exec mail grep -i 'connect to 127.0.0.1:10023: Connection refused' /var/log/mail/mail.log
   assert_failure