I’m happy to report that Concrete CMS 8.5.6 is now available.
https://www.concretecms.org/download
There are a handful of new features in this release, but most of this release is for the purpose of fixing the marketplace (which has had connection issues for several month across several browsers) and making some security fixes available. Full release notes can be found here:
https://documentation.concretecms.org/developers/introduction/version-history/856-release-notes