Unavailable since version 4.0.0.
There is no known sponsor or interested party for implementing Z39.50. Interested parties may contact the project team for guidance and to express their intent.
Z39.50 is the name of an older communication protocol used for distributed searching across metadata catalogs.
Upgrading from GeoNetwork 3.0 Guidance
Z39-50 API is no longer available.
Recommend migrating to use of Catalog Service for the Web (CSW) API.