Works with CiviCRM 4.2. It might not be supported anymore.
This API gets all activties (is_current_revision=1) for a case_id (including targets and assignees)
Releases
Since CiviCRM 5.x, extension releases compatible with CiviCRM 5.0 are compatible with 5.0 and later. An extension release compatible with 5.25, for example, means that it requires CiviCRM 5.25 or later.