We have started experimenting with new modules for next-gen projects. While it was already possible to extend the issue details view, we are adding new integration points for apps on the boards and backlogs. It is now possible to add a button to both the board and the backlog in next-gen projects.
See the documentation for more details.
If you have extended the classic project boards before, you might have used a web section that renders as a drop-down menu. We have decided to use buttons only for now.
The public REST API works with next-gen projects, but we are aware of its limitations. See this topic for more details.
Both the APIs and the new modules are likely to change in the future. If you have any questions or feedback, please share it here!