Looking at the Issues tab on the Flexx Github repo, there is this statement by the creator -" Personally, I have moved on to other things and don't want to spent much time on Flexx anymore. I still find it an interesting project though, and I can try to find time to do some minimal maintenance or advice to e.g. keep adjusting to new Python versions."
This doesn't sound promising for keeping leoflexx working, does it?