Certain operations can only be performed on IN_PROGRESS tasks. These include Update Task Data and all file upload operations. Other operations – such as Reopen Task –can only be performed on tasks that are DONE. When a client attempts to perform one of these operations on a task whose status is WAITING, the request will be rejected.
For more about WAITING, IN_PROGRESS and DONE, see Task Life Cycle,
For more about Task Upload operations, see Task Upload.