[adriaanm]

The Scala 2.x series is for source compatible releases. The goal is that you can just recompile your Scala 2.11 code on Scala 2.12. (As was the case for the upgrade from 2.10 to 2.11 -- modulo some changes necessary for important bug fixes.)

We're reserving the bigger version bump for when source compatibility is not fully maintained. We take backwards compatibility very seriously, so the jump will be as small as we can make it (balanced with the need to keep evolving and improving the language). We'll share our thoughts on Scala's longer-term roadmap once they've crystallized (soon!).