Hi,
the main reason for no releases since 2019 is, that my policy was to create a release once I could test OpENer on the European plugfest.
However, Corona made that impossible for some time, and I recently got a new job, so my time for developing OpENer is not funded anymore, and taking part at a plugfest takes some considerable cost (travel, hotel, participation fee), which I do not want to fund from my current income.
The Security branch isn't fully working, however the master branch should work. Please keep in mind specifications changes have not been incorporated into OpENer.
Cheers