diff --git a/Changelog.rst b/Changelog.rst
index a05dec2..4a4db93 100644
--- a/Changelog.rst
+++ b/Changelog.rst
@@ -5,7 +5,15 @@ ChangeLog
 :website: http://offlineimap.org
 
 
-OfflineIMAP v6.5.6 (YYYY-MM-DD)
+OfflineIMAP v6.5.6.1 (YYYY-MM-DD)
+=================================
+
+* Fix mangled message headers for servers without UIDPLUS:
+  X-OfflineIMAP was added with preceeding '\n' instead of
+  '\r\n' just before message was uploaded to the IMAP server.
+
+
+OfflineIMAP v6.5.6 (2014-05-14)
 ===============================
 
 * Fix IDLE mode regression (it didn't worked) introduced
diff --git a/offlineimap/folder/Base.py b/offlineimap/folder/Base.py
index 43e79ff..bca52a2 100644
--- a/offlineimap/folder/Base.py
+++ b/offlineimap/folder/Base.py
@@ -413,16 +413,26 @@ next line\n
 
     """
 
-    def addmessageheader(self, content, headername, headervalue):
+    def addmessageheader(self, content, crlf, headername, headervalue):
+        """
+        Adds new header to the provided message.
+
+        Arguments:
+        - content: message content, headers and body as a single string
+        - crlf: string that carries line ending
+        - headername: name of the header to add
+        - headervalue: value of the header to add
+
+        """
         self.ui.debug('',
                  'addmessageheader: called to add %s: %s' % (headername,
                                                              headervalue))
-        prefix = '\n'
+        prefix = crlf
         suffix = ''
-        insertionpoint = content.find('\n\n')
+        insertionpoint = content.find(crlf + crlf)
         if insertionpoint == 0 or insertionpoint == -1:
             prefix = ''
-            suffix = '\n'
+            suffix = crlf
         if insertionpoint == -1:
             insertionpoint = 0
             # When body starts immediately, without preceding '\n'
@@ -430,8 +440,8 @@ next line\n
             # we seen many broken ones), we should add '\n' to make
             # new (and the only header, in this case) to be properly
             # separated from the message body.
-            if content[0] != '\n':
-                suffix = suffix + '\n'
+            if content[0:len(crlf)] != crlf:
+                suffix = suffix + crlf
 
         self.ui.debug('', 'addmessageheader: insertionpoint = %d' % insertionpoint)
         headers = content[0:insertionpoint]
diff --git a/offlineimap/folder/Gmail.py b/offlineimap/folder/Gmail.py
index f051938..2a598de 100644
--- a/offlineimap/folder/Gmail.py
+++ b/offlineimap/folder/Gmail.py
@@ -93,7 +93,7 @@ class GmailFolder(IMAPFolder):
                 labels = set()
             labels = labels - self.ignorelabels
             labels_str = imaputil.format_labels_string(self.labelsheader, sorted(labels))
-            body = self.addmessageheader(body, self.labelsheader, labels_str)
+            body = self.addmessageheader(body, '\n', self.labelsheader, labels_str)
 
         if len(body)>200:
             dbg_output = "%s...%s" % (str(body)[:150], str(body)[-50:])
diff --git a/offlineimap/folder/GmailMaildir.py b/offlineimap/folder/GmailMaildir.py
index 3f37b02..be0d20d 100644
--- a/offlineimap/folder/GmailMaildir.py
+++ b/offlineimap/folder/GmailMaildir.py
@@ -141,7 +141,7 @@ class GmailMaildirFolder(MaildirFolder):
         # Change labels into content
         labels_str = imaputil.format_labels_string(self.labelsheader,
           sorted(labels | ignoredlabels))
-        content = self.addmessageheader(content, self.labelsheader, labels_str)
+        content = self.addmessageheader(content, '\n', self.labelsheader, labels_str)
         rtime = self.messagelist[uid].get('rtime', None)
 
         # write file with new labels to a unique file in tmp
diff --git a/offlineimap/folder/IMAP.py b/offlineimap/folder/IMAP.py
index 4801eef..3b506e5 100644
--- a/offlineimap/folder/IMAP.py
+++ b/offlineimap/folder/IMAP.py
@@ -526,6 +526,7 @@ class IMAPFolder(BaseFolder):
         # NB: imapobj to None.
         try:
             while retry_left:
+                # XXX: we can mangle message only once, out of the loop
                 # UIDPLUS extension provides us with an APPENDUID response.
                 use_uidplus = 'UIDPLUS' in imapobj.capabilities
 
@@ -535,7 +536,7 @@ class IMAPFolder(BaseFolder):
                                                     content)
                     self.ui.debug('imap', 'savemessage: header is: %s: %s' %\
                                       (headername, headervalue))
-                    content = self.addmessageheader(content, headername, headervalue)
+                    content = self.addmessageheader(content, CRLF, headername, headervalue)
 
                 if len(content)>200:
                     dbg_output = "%s...%s" % (content[:150], content[-50:])