Liferay’s workflow engine calls users to participate in a review process designed for them. Out of the box, workflow makes it possible to define simple to complex business processes/workflows, deploy them, and manage them through a portal interface.
Workflow is flexible, in that you can design workflow processes in XML to suit your business needs.
In Liferay DXP version 7.2, a new set of workflow features was introduced around the concept of Workflow Metrics.
The embedded calendar that ships out of the box can be replaced by your own custom calendar service. More customization points will likely be added in the future.