Not all platforms in Shen have the potential to support concurrency; as of 2013, Javascript has no concurrent support. Of the other platforms, Clojure and Java do support concurrency, but no concurrnet support has been developed for Shen on these platforms. Concurrency is not part of the CL specification though SBCL supports it.

Currently the only Shen supporting integrated type secure concurrency with Shen is Shen Professional.