looking at the New-Releases
directory-opus-12-is-now-available Sep 5, 2016
directory-opus-11-is-now-available Mar 3, 2014
directory-opus-10-now-available Apr 30, 2011
directory-opus-9-now-available Apr 28, 2007
So its at least 2 years between major releases. In that respect Opus 12 is still quite new. I would expect opus 13 around 2018/2019. Historically they release quite a number of new features for free in minor releases.