SORT capability

[absolutely_free at libero.it]

Hi,

why I don't see SORT capability on my dovecot server?

# telnet localhost 143
Trying ::1...
Connected to localhost.
Escape character is '^]'.
* OK [CAPABILITY IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID ENABLE IDLE STARTTLS AUTH=PLAIN AUTH=LOGIN AUTH=DIGEST-MD5 AUTH=CRAM-MD5] Dovecot ready.
1 capability
* CAPABILITY IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID ENABLE IDLE STARTTLS AUTH=PLAIN AUTH=LOGIN AUTH=DIGEST-MD5 AUTH=CRAM-MD5
1 OK Capability completed.
a logout
* BYE Logging out
a OK Logout completed.
Connection closed by foreign host.

I am using 

# dovecot --version
2.0.9

default CentOS rpm package.
Thank you