The new [experimental] web UI is based on Flask App Builder [FAB] to which we contributed security fixes recently.
It's been hard to get the main maintainer of the project's attention to release to Pypi. For context, I have write access to the repository, but no access to release to Pypi. Please show your support by adding reactions or nice, supportive comments on https://github.com/dpgaspar/Flask-AppBuilder/issues/808 If you think it's a very useful and cool project (which it is!) and have a bit of extra time you can commit, you can offer help maintaining the project as well as clearly the two people with write access to the repo have their hands full. Thanks! Max