sorting order by date

[flexiblebird]

I do not know if this has been reported in the old bugtracker before, and I do not know if it is a user problem, and I do not know if bugs will be fixed in this year old software, but when I display the inbox and other lists sorted by send date or receiving date, the list is sorted using the date as an alphabetical string and this is not %y-%m-%d but in my country %d.%m.%y and this will mess up things completley, the lists are unusable, all emails from day 31 of every year and month intermixed on top, below this all emails that date on day 30 and so on.
As I can not believe that Sylpheed has no users outside asia, I probably miss some important configuration setting. Using Windows 11 in Germany with german language settings.