Usually, we update the versions of JDT, Equinox, and p2 to the latest milestone before a release.
AFAIK, Tycho 0.15 includes the JDT version with
bug 384663, so we should have a bug report for this in Tycho (as a reminder to update the JDT version). Is the problem described in Tycho
bug 382408 caused by the JDT bug?