Scala 2.12.0 has been release yesterday. It is a major update, see also
I was a bit too quick to follow: .0 only means another release candidate
in the Scala universe. So 85adb337e32f is now mostly reverted by
People who want to test scala-2.12.0 nonetheless, can do that by a line
in $ISABELLE_HOME_USER/etc/settings like this:
For our Isabelle2016-1 release, which is as always meant to be stable
and unchangeable, we will stick to stable scala-2.11.8.
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