The CV appears old. His recent position is listed as starting July 2010 to present, but looking at his LinkedIn we see his finished at Mozilla in 2011. https://www.linkedin.com/in/paulbiggar/

Can read about how CircleCI's continued use of Clojure in 2017: https://circleci.com/blog/tips-for-optimizing-docker-builds/ And again in 2019: https://circleci.com/blog/update-how-circleci-processes-over...