I've updated from Cyrus IMAPd 2.0.4 (stable) to Cyrus IMAPd 2.1.4 (development). I needed doing that because the way the older version handled RFC 2047(???) non-compliant 8 bit headers. It simply replaced 8 bit chars with an 'X'.
Now I'm having some troubles making it work again... I'm not reading my e-mail since yesterday night...