Thank you very much for the Czech translation Michal Janata, and for the fork Phil Derksen 🙂
It is the same for Czech. Disagrees date and name of day (shifted by one).
In Simple Calendar:
18. November = Čt (Thursday)
In effect:
18. November = St (Wednesday)
When I set “Advanced” -> “Week starts on” -> “Custom” … shifted by one remains