I have just updated the plugin to fix the errors discovered by @CaraRae. These are Qt6 migration issues that I missed. There are no changes to any functions in the plugin.
The release notes are:
- Fix: Qt6 compatiblility - Prefs viewer tab stops and file chooser for database backup.
As usual, calibre will announce the update in the next hour or so. And any problems with the plugin should be reported here.