--text follows this line--
The Courier-IMAP server(s) listening at mail.panix.com annouce support
for the UIDPLUS capability described in RFC 2359, but don't support it
in practice.

Here's the Capability string, reformatted for display:

,----
| * OK [CAPABILITY IMAP4rev1
|       UIDPLUS
|       CHILDREN NAMESPACE THREAD=REFERENCES
|       SORT QUOTA IDLE AUTH=PLAIN]
|       Courier-IMAP ready. Copyright 1998-2005 Double Precision, Inc.
|       See COPYING for distribution information.
`----

Note that UIDPLUS is present.

When I issue an APPEND or COPY command, the server responds with a
traditional, non-UIDPLUS-related string:

,----
| 25 APPEND "INBOX.test" {200057}
| ...
| 25 OK Append completed.
`----

Looking in Section 4.2 of the RFC¹, the server should have included an
APPENDUID clause in between "OK" and "Append" above.

My IMAP client is failing when copying and storing messages on the
server because of this false advertisement of UIDPLUS support. Is this a
feature that's been disabled by a configuration directive? Either the
server should not be advertising this capability, or it should actually
support it as advertised.


Footnotes: 
¹ http://www.faqs.org/rfcs/rfc2359.html

-- 
Steven E. Harris