We're happy to announce the release of Stardog 6.0.0. This version most notably contains virtual graph support for MongoDB, among other enhancements, which you can read about in the release notes.
It is important to note that the 6.0.0-alpha2 release previously available in this forum (codename "Mastiff" and featuring a RocksDb-backed storage engine) is unrelated to what has become the official Stardog 6. Those changes are currently slated for the 7.x release cycle.