Python GUIs for Humans! PySimpleGUI is the top-rated Python application development environment. Launched in 2018 and actively developed, maintained, and supported in 2024. Transforms tkinter, Qt, ...
Previously LGPL, now re-licensed as closed-source/commercial. Previous code taken down.
Commercial users pay $99/year, free for personal use but each user has to make a free account after a trial period.
Previous versions licensed under LGPL will remain licensed as such. The current maintainers have no obligation to contribute distributing the older versions, but they aren't permitted to prevent others from distributing it or modifying or doing anything else that was permitted by the license.
And, yes, to change from GPL/LGPL to another license you would need all of the contributors to consent, or to rewrite the parts that were contributed by anyone who doesn't agree with the license change. Since it looks like there only one contributor according to the GitHub page, this probably wasn't too difficult.
https://news.ycombinator.com/item?id=39369886 outlines the (non) PR history. Expand the whole HN post to get links of (unrelated) people who cloned the LGPL v4 tree/tag/branch before they (PySimpleSoft) scrubbed/deleted the entire Github repo of pre-v5 content the past few days.