And apparently there has been some continuation until 2013, see http://occam-pi.org/

Here are even some github projects with commits until 2020: https://github.com/concurrency

And here is even more interesting stuff: https://web.archive.org/web/20190923093909/http://www.transt.../ and https://web.archive.org/web/20230610081628/http://concurrenc.../