You get the core Activiti process engine in version 5.19 embedded into ACS 5.2 which allows you to execute processes and expose them via the Share user interface or ACS ReST API endpoints (limited exposure of Activiti specific features due to a generic workflow abstraction layer). Integration as an embedded engine is superior to the APS + ACS use case as processing tasks etc. is transactionally safe and access to ACS APIs is more extensive via Script APIs or Java APIs. On the other hand, there is no runtime modelling of processes or forms, limited/no support for integration with other services without doing custom development, and a lot of Activiti functionality is hidden behind the workflow abstraction API, which requires circumventing the officially documented / supported Java APIs of ACS to be used.
