diff --git a/51-filter-postfix-aggregate.conf b/51-filter-postfix-aggregate.conf
deleted file mode 100644
index 0a6cd03..0000000
--- a/51-filter-postfix-aggregate.conf
+++ /dev/null
@@ -1,40 +0,0 @@
-filter {
-  if ![postfix_queueid] {
-    drop {}
-  } else if [postfix_queueid] == "NOQUEUE" {
-    drop {}
-  } else if [program] == "postfix/qmgr" and [postfix_from] {
-    aggregate {
-      task_id => "%{postfix_queueid}"
-      code => "
-        map['postfix_from'] = event.get('postfix_from')
-        map['postfix_size'] = event.get('postfix_size')
-        map['postfix_nrcpt'] = event.get('postfix_nrcpt')
-      "
-    }
-  } else if [program] == "postfix/smtpd" {
-    aggregate {
-      task_id => "%{postfix_queueid}"
-      code => "
-        map['postfix_client_hostname'] = event.get('postfix_client_hostname')
-        map['postfix_client_ip'] = event.get('postfix_client_ip')
-      "
-    }
-  } else if [program] == "postfix/cleanup" {
-    aggregate {
-      task_id => "%{postfix_queueid}"
-      code => "
-        map['postfix_message-id'] = event.get('postfix_message-id')
-      "
-    }
-  } else if [program] == "postfix/smtp" {
-    aggregate {
-      task_id => "%{postfix_queueid}"
-      code => "
-       map.each do |key, value|
-         event.set(key, value)
-       end
-     "
-    }
-  }
-}
diff --git a/README.md b/README.md
index 717ec43..a4f3e9c 100644
--- a/README.md
+++ b/README.md
@@ -19,18 +19,6 @@ The included Logstash config file requires two input fields to exist in input ev
 
 This event format is supported by the Logstash `syslog` input plugin out of the box, but several other plugins produce input that can be adapted fairly easy to produce these fields too. See [ALTERNATIVE INPUTS](ALTERNATIVE-INPUTS.md) for details.
 
-Aggregation filter
------
-
-A optional aggregation filter is available, that will combine fields from different log lines. The key on which log lines are aggregated is the postfix queue id. For example:
-
-![Alt text](aggregation_example_pic.jpg?raw=true)
-
-In this example, the `postfix_from` field from a `postfix/qmgr` log line is reused, and added to a log line from `postfix/smtp`.
-
-To use the aggregation filter, add `51-filter-postfix-aggregate.conf` to `/etc/logstash/conf.d` or `pipeline` dir for dockerized Logstash.
-
-
 Tests
 -----
 
diff --git a/aggregation_example_pic.jpg b/aggregation_example_pic.jpg
deleted file mode 100644
index c99db70..0000000
Binary files a/aggregation_example_pic.jpg and /dev/null differ