1 files changed, 14 insertions, 0 deletions
diff --git a/imap.c b/imap.c
index 3234b3b5..f1d5a225 100644
--- a/imap.c
+++ b/imap.c
@@ -620,6 +620,19 @@ static int imap_delete(int sock, struct query *ctl, int number)
     return(PS_SUCCESS);
 }
 
+static flag imap_retain_check(int num, char *buf)
+/* is this a special message that should be retained? */
+{
+    /*
+     * The University of Washington IMAP server (the reference
+     * implementation of IMAP4 written by Mark Crispin) relies
+     * on being able to keep base-UID information in a special
+     * message at the head of the mailbox.  This message should
+     * neither be deleted nor forwarded.
+     */
+    return (num == 1 && !strncasecmp(buf, "X-IMAP:", 7));
+}
+
 const static struct method imap =
 {
     "IMAP",		/* Internet Message Access Protocol */
@@ -636,6 +649,7 @@ const static struct method imap =
     imap_fetch_body,	/* request given message body */
     imap_trail,		/* eat message trailer */
     imap_delete,	/* delete the message */
+    imap_retain_check,	/* leave this message alone? */
     "LOGOUT",		/* the IMAP exit command */
 };