Following the suggestions made in this thread, I have updated my ePubTidyTool plugin so that it will check this website for updates.
The code is in a self-contained module called checkVersion.py and it uses the version of Beautiful Soup that is built into Sigil. Other plugin developers could, if they wished, extract this file from the zip plugin and use it in their own projects.
The plugin can be downloaded from:
https://www.mobileread.com/forums/sho...54#post3228354)