New Features (ENH)
- Add AES support for encrypting PDF files (1918, 1935, 1936, 1938)
- Add page deletion feature to PdfWriter (1843)
Bug Fixes (BUG)
- PdfReader.get_fields() attempts to delete non-existing index "/Off" (1933)
- Remove unused objects when cloning_from (1926)
- Add the TK.SIZE into the trailer (1911)
- add_named_destination() maintains named destination list sort order (1930)
[Full Changelog](https://github.com/py-pdf/pypdf/compare/3.11.1...3.12.0)