Previously the sorting by serial enumeration in biblio's holdings table was using published date (see bug: https://bugs.koha-community.org/bugzilla3/show_bug.cgi?id=13420). In version 24.05 sorting doesn't seem to be using the date anymore. Sorting is now done based on the string in "h - Serial Enumeration / chronology item" field, so e.g. after number "2024 : 1" comes "2024 : 10" and so on. Has this been changed by accident when we shifted to displaying items via REST API on holdings table?