Week numbering - weeks starting day

we have version 3.0.3005
wek numbering - i can se that several have had questions about this before.
Though i change to correct langue, the week numbering in incorrect.
It looks to me as the problems comes from when the week starts - what day is the starting day on the week.
Gant let the week start on sundays. We - microsoft also - late the week starts on mondays.
example: today it is the 09.04.2121 - ninth of april 2121.
Gant shows this as week no 15. But our official week no is week no 14.
Is there anyway i can set this to be correct.

If you’re using English translation, make sure to choose English (United Kingdom).

This is a quite interesting questing, because in my GanttProject (3.0.3005 on Mac OS X 10.15.7) I can’t see any calendar week numbers and there is no preference to activate those. I can remember older versions, where I was able to select the start day of the week.

@DmitryBarashev is calendar week numbering actually disabled?

What do you mean when you say “calendar week numbering disabled”?

There are week numbers in the chart timeline. We use week numbers provided by Java Runtime. Java calculates them from the locale which is set by choosing interface language. “English” is actually en-US in GanttProject, “English (United Kingdom)” is the same translation, but with en-GB locale and different locale settings, including first week of year and first day of week.

Ah – my fault! The week numbers disappear below a specific zoom level and I’m nearly constantly working zoomed in.

yesy. but danish is different.
but anyway. fine