1 files changed, 14 insertions, 0 deletions
diff --git a/pop3.c b/pop3.c
index 59f1da7e..e5e26299 100644
--- a/pop3.c
+++ b/pop3.c
@@ -342,6 +342,19 @@ static int pop3_delete(int sock, struct query *ctl, int number)
     return(gen_transact(sock, "DELE %d", number));
 }
 
+static flag pop3_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 pop3 =
 {
     "POP3",		/* Post Office Protocol v3 */
@@ -358,6 +371,7 @@ const static struct method pop3 =
     NULL,		/* no way to fetch body alone */
     NULL,		/* no message trailer */
     pop3_delete,	/* how to delete a message */
+    pop3_retain_check,	/* try not to nuke an IMAP4rev header message */
     "QUIT",		/* the POP3 exit command */
 };