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

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?