So an update on this - it turns out that Scala 2.12 will require some changes to various dependencies, most notably Specs2 (and its transitive dependencies on Scalaz) and json4s.
Per discussions on the github issue(s), there is not a strong demand for Scala 2.12.x support just now. Rather, multiple people are asking for Casbah 3.1.1 support.
Scala 2.12 may come in the future if demand is high enough (or when 2.11 reaches eol) - and as always - pull requests are welcome.
On Monday, November 7, 2016 at 10:08:42 AM UTC-5, Claudio Pacchiega wrote: