diff --git a/aprslib/parsing/message.py b/aprslib/parsing/message.py
index 3995629..e06ef88 100644
--- a/aprslib/parsing/message.py
+++ b/aprslib/parsing/message.py
@@ -72,25 +72,99 @@ def parse_message(body):
         else:
             logger.debug("Packet is just a regular message")
             parsed.update({'format': 'message'})
+            has_matched = False
 
+            # APRS supports two different message formats:
+            # - the standard format which is described in 'aprs101.pdf':
+            #   http://www.aprs.org/doc/APRS101.PDF
+            # - an addendum from 1999 which introduces a new format:
+            #   http://www.aprs.org/aprs11/replyacks.txt
+            #
+            # A message (ack/rej as well as a standard msg text body) can either have:
+            # - no message number at all
+            # - a message number in the old format (1..5 characters / digits)
+            # - a message number in the new format (2 characters / digits) without trailing 'ack msg no'
+            # - a message number in the new format with trailing 'free ack msg no' (2 characters / digits)
+
+            #
+            # ack / rej parser
+            #
+            # search for: ack/rej new format with msgNo present and ackMsgNo present
+            if not has_matched:
+                match = re.search(r"^(ack|rej)([A-Za-z0-9]{2})}([A-Za-z0-9]{2})$", body)
+                if match:
+                    parsed.update({
+                        'response': match.group(1),
+                        'msgNo': match.group(2),
+                        'ackMsgNo': match.group(3)
+                    })
+                    if "message_text" in parsed:
+                        parsed.pop("message_text")
+                    has_matched = True
+
+            # search for: ack/rej new format with msgNo present and ackMsgNo not present
+            if not has_matched:
+                match = re.search(r"^(ack|rej)([A-Za-z0-9]{2})}$", body)
+                if match:
+                    parsed.update({
+                        'response': match.group(1),
+                        'msgNo': match.group(2),
+                    })
+                    if "message_text" in parsed:
+                        parsed.pop("message_text")
+                    has_matched = True
+
+            # search for: ack/rej standard format as per aprs101.pdf chapter 14
             match = re.search(r"^(ack|rej)([A-Za-z0-9]{1,5})$", body)
             if match:
                 parsed.update({
                     'response': match.group(1),
                     'msgNo': match.group(2),
                     })
-            else:
-                body = body[0:70]
+                if "message_text" in parsed:
+                    parsed.pop("message_text")
+                has_matched = True
 
-                match = re.search(r"{([A-Za-z0-9]{1,5})$", body)
+            #
+            # regular message body parser
+            #
+            if not has_matched:
+                # new message format: http://www.aprs.org/aprs11/replyacks.txt
+                # search for: msgText/msgNo/ackMsgNo all present
+                match = re.search(r"{([A-Za-z0-9]{2})}([A-Za-z0-9]{2})$", body)
                 if match:
                     msgNo = match.group(1)
-                    body = body[:len(body) - 1 - len(msgNo)]
-
+                    ackMsgNo = match.group(2)
+                    body = body[:len(body) - 3 - len(msgNo) - len(ackMsgNo)]
                     parsed.update({'msgNo': msgNo})
+                    parsed.update({'ackMsgNo': ackMsgNo})
+                    has_matched = True
+                    parsed.update({'message_text': body[0:67].strip()})
 
-                parsed.update({'message_text': body.strip(' ')})
+            # new message format: http://www.aprs.org/aprs11/replyacks.txt
+            # search for: msgText/msgNo present and ackMsgNo not present
+            if not has_matched:
+                match = re.search(r"{([A-Za-z0-9]{2})}$", body)
+                if match:
+                    msgNo = match.group(1)
+                    body = body[:len(body) - 2 - len(msgNo)]
+                    parsed.update({'msgNo': msgNo})
+                    has_matched = True
+                    body = body[0:67].strip()
+                    parsed.update({'message_text': body[0:67].strip()})
 
-        break
+            # old message format - see aprs101.pdf.
+            # search for: msgNo present
+            if not has_matched:
+                    match = re.search(r"{([A-Za-z0-9]{1,5})$", body)
+                    if match:
+                        msgNo = match.group(1)
+                        body = body[:len(body) - 1 - len(msgNo)]
+                        parsed.update({'msgNo': msgNo})
+                        has_matched = True
+                        parsed.update({'message_text': body[0:67].strip()})
+
+            # break free from the eternal 'while'
+            break
 
     return ('', parsed)