With Isabelle/42b92fa72a51 we are on a pre-release version of Poly/ML
5.7. David Matthews is about to converge to a release.
There are various changes in the runtime system, and a few ones in the
compiler (more PIDE markup). For example, local identifier scopes are
visualized in the Isabelle/ML IDE as for the logical term language.
isabelle-dev mailing list