Functionality to list assets and attachments by organization (org.assets.fetch(...) and org.attachments.fetch(...)) will soon be deprecated. This will be a breaking change for all versions.
Clients wishing to fetch these resources for an entire organization should instead list all Brandfolders for that organization, and then iteratively fetch assets or attachments from each section within a Brandfolder.
See the API documention for listing assets and listing attachments for more information: