It is currently not possible to compile a What's New based on the documentation and script alone - further knowledge is also required. Changes needed:

• Add two other types of contribution to the developer's guide and to aggregate_directory.py:
  • Dependency updates
  • Breaking changes (only expected for major releases)
• Developer's guide: provide guidance on the manual work needed after the aggregate script has run:
  • Adding showcases
  • Building a local html to check all formatting, spelling and link functionality
• Address the horizontal lines added by the aggregate script:
  • Find a way to cope without them (they have been added due to difficulties with reST)
  • OR document in the developer's guide that they need to be manually removed
• Developer's guide: document the step where index.html is changed so that the What's New link points to the newly created file.
• Notes on removing the contribution folder when done?

See also #2104 for notes on documentation clarity