a command-line interface was added with subcommands 'show' and 'codify'.
improvements or new methods for private tags, JSON handling, FileSets, and VRs of AT, DS, and PersonName.
improvements in color space conversion and RLE encoding/decoding.
Data dictionaries were updated to version 2021b of the DICOM Standard
There were many bug fixes and other changes; see the release notes for full details of changes, additions, and bug fixes.