OpenXP 5
OpenXP 5 - a multi-protocol offline mail and news reader
...It is based on OpenXP (https://sourceforge.net/p/openxp, currently inactive) which is based on CrossPoint (XP) by Peter Mandrella.
OpenXP 5 is capable of establishing TLS encrypted connections to POP3, IMAP, SMTP and NNTP based servers and supports the new IPv6 protocol.
see:
http://de.wikipedia.org/wiki/CrossPoint
http://svn.code.sf.net/p/openxp5/code/doc/Crosspoint_Versions.pdf
http://groups.google.com/forum/#!forum/de.comm.software.crosspoint