The version of Unison currently in the Breezy repository is 2.10. The current stable version is 2.13.16; this is also the version my Gentoo server installs by default. (It also offers 2.9, 2.12 and 2.17; 2.10 is not available at all.) Since the major and minor versions of the client's copy of Unison have to match with the server's, this left me unable to use Unison until I downloaded a binary from the author's site, which was rather inconvenient.
Hence, I'd like to see Unison updated to 2.13.16.