We finally have new mail server. Thanks to Czech company Cybersales , we are running latest mail technology based on Linux. Our mail server is powered by postfix, supports secure imap and pop3, spamassassin helps to get rid of spam and we use Fedora LDAP server for user accounts.
Now I can finally have a good sleep at night :-). If the new mail server will work at least as long as the old one, it would be great.