diff --git a/README.rst b/README.rst
index 47cb2a8..b4bdccc 100644
--- a/README.rst
+++ b/README.rst
@@ -147,13 +147,15 @@ The user discussion, development and all exciting stuff take place in the
 `mailing list`_. You're *NOT* supposed to subscribe to send emails.
 
 
-Reporting bugs
-==============
+Reporting bugs and contributions
+================================
 
 Bugs
 ----
 
-Bugs and issues should be reported to the `mailing list`_.
+Bugs, issues and contributions should be reported to the `mailing list`_.
+**Please, don't use the github features (messages, pull requests, etc) at all.
+It would most likely be discarded or ignored.**
 
 
 ========
diff --git a/offlineimap/folder/IMAP.py b/offlineimap/folder/IMAP.py
index e3ce419..76f0c4a 100644
--- a/offlineimap/folder/IMAP.py
+++ b/offlineimap/folder/IMAP.py
@@ -87,9 +87,13 @@ class IMAPFolder(BaseFolder):
             # Primes untagged_responses
             imapobj.select(self.getfullname(), readonly = 1, force = 1)
             try:
-                # Some mail servers do not return an EXISTS response if
-                # the folder is empty.
-                maxmsgid = long(imapobj.untagged_responses['EXISTS'][0])
+                # 1. Some mail servers do not return an EXISTS response
+                # if the folder is empty.  2. ZIMBRA servers can return
+                # multiple EXISTS replies in the form 500, 1000, 1500,
+                # 1623 so check for potentially multiple replies.
+                maxmsgid = 0
+                for msgid in imapobj.untagged_responses['EXISTS']:
+                    maxmsgid = max(long(msgid), maxmsgid)
             except KeyError:
                 return True
 
@@ -169,10 +173,13 @@ class IMAPFolder(BaseFolder):
                     return
             else:
                 try:
-                    # Some mail servers do not return an EXISTS response if
-                    # the folder is empty.
-
-                    maxmsgid = long(imapobj.untagged_responses['EXISTS'][0])
+                    # 1. Some mail servers do not return an EXISTS response
+                    # if the folder is empty.  2. ZIMBRA servers can return
+                    # multiple EXISTS replies in the form 500, 1000, 1500,
+                    # 1623 so check for potentially multiple replies.
+                    maxmsgid = 0
+                    for msgid in imapobj.untagged_responses['EXISTS']:
+                        maxmsgid = max(long(msgid), maxmsgid)
                     messagesToFetch = '1:%d' % maxmsgid;
                 except KeyError:
                     return