You can find the list of changes made in schema version 5.3.1 compared to the prior version (4.8.1) on our documentation site.
The xml snippet you posted uses the JATS schema, not the Crossref schema. Are you asking how that same information (author names and affiliation) would be formatted in our 5.3.1 schema?
The equivalent author metadata would look like this
<person_name sequence="first" contributor_role="author">
<given_name>Melvin P.</given_name>
<surname>Weinstein</surname>
<affiliations>
<institution>
<institution_name>UMDNJ-Robert Wood Johnson Medical School</institution_name>
<institution_acronym>RWJMS</institution_acronym>
<institution_place>New Brunswick, NJ</institution_place>
<institution_department>Departments of Medicine and Pathology</institution_department>
</institution>
</person_name>
You can see an example deposit with multiple authors and multiple institutional affiliations here.