When a workflow is a sub-process workflow, what must be true before it can be referenced in another workflow?

For a sub-process workflow to be referenced in another workflow, it is essential that it is enabled and active. This ensures that the sub-process is ready for execution when called upon by the main workflow. If the sub-process is not enabled and active, the main workflow will not be able to invoke it during its execution, which would lead to failures or inconsistencies in the workflow processes.

The other considerations, while important for workflow management, do not specifically determine the ability of the sub-process to be referenced. For instance, completion and approval may relate more to the validation of a workflow rather than its reference capability. Similarly, having all tasks defined is crucial for the flow within that sub-process but does not directly impact its usability in another workflow. Lastly, documentation and publication are more about communication and visibility of the workflow rather than its active status for use, making them secondary to the requirement of being enabled and active.