- Remove the add-on store repository
- Download an old release from https://github.com/fl4p/batmon-ha/tags
- Extract the contents of the ZIP file into Home Assistant's
/addons/batmon-hafolder (using FTP, Samba Share, etc.). - The add-on will appear in the add-on store under "Local Addons" (click 'Check for updates')