Release Notes can be found here.
Cromwell is the workflow execution service used to run and test WDL workflows. When creating WDL workflows, you can test on a local installation of the Cromwell execution engine prior to uploading and testing on FireCloud. Cromwell reads WDL, which describes workflows of executable tasks packaged into Docker containers. Cromwell then calls Google’s Pipelines API (PAPI) to run the executable tasks packaged within Docker containers.