[Dovecot] How to disable SSL and TLSv1.1?

[Darren Pilgrim]

I'm running Dovecot 2.2.5 and want to make it refuse SSLv2, SSLv3 and 
TLSv1.0.  Clients will opportunistically use TLS 1.1 and 1.2, but now I 
want require they do so.  Is it enough to set

ssl_cipher_list = HIGH:!SSLv2:!SSLv3:!TLSv1.0:!aNULL:!MD5
or are there additional settings I need to specify?