Hi,
We are aware of the unfortunate state of not having made a release for a long while. We have had a release branch for 6.3.0 that we think is generally stable and ready for a long time (which is also used in the MiniZinc IDE). You can definitely use that if you want to get all the recent fixes.
There are several complications in making the release at this moment, but we are hoping to get it done sooner rather than later. Unfortunately, we have no time-lime that we can commit to at this time.
Cheers,
Mikael