Out of box, only Published Knowledge Articles can be accessed/searched for in the Knowledge Homepage/Portal. The system property glide.knowman.show_unpublished, if set to 'true', allows users the ability to search for unpublished KB articles set in either Draft or Review workflow states.
There are two supplementary system properties used to give specific roles access to KB articles in respected Draft or Review workflow states:
*If you wish to give users access/search access to KB articles in other or custom workflow states, you need to configure this within the Knowledge Properties page.
An example of this might look like: pending_retirement: admin,itil_admin
An example of adding multiple custom workflow states would appear like: pending_retirement: admin,itil_admin;pending_publish: admin
Note: workflow states are separated by roles with a colon (:) whereas groups of workflow_state: role are separated by semi-colons (;)