In our recent R11.4 release we made an important change to the M-Box POP/IMAP
Gateway product which we launched in December of last year.
This product now operates in 'synchronization mode', which manages its
relationship with the backend POP server to which it connects. Prior to R11.4
when the gateway connected to the POP server to download messages, those
messages were deleted on the POP server.
Now messages are deleted on the POP server only if the client deletes the
message on the M-Box POP/IMAP gateway. Both servers remain in sync.