It has been 18 (!) years since Crossref last deprecated a metadata schema. In that time, we’ve released numerous schema versions, some major updates, and some interim releases that never saw wide adoption. Now, with 27 different schemas to support, we believe it’s time to streamline and move forward.
This is a companion discussion topic for the original entry at https://www.crossref.org/blog/its-time-planning-for-metadata-schema-deprecation