avconv way behind

[MR ZenWiz]

On Xubuntu 14.04.4 (4.2.0-42 kernel) I've been getting a fair number
of "warnings" that my avconv, v. 9.18-6:9.18-0ubuntu0.14.04.1 is
severely out of date.

The most recent release of avconv is 11.7.

Is this because of the "old" version of Xubuntu I'm running, ro do I
need a different repository for the newer version, or should I just
use the latest from avconv directly, or ...?

Thanks.
MR