Feature: Change date format

[MalcolmMielle]

I would be nice if the date format when adding an expense followed the format of the language/zone. E.g. instead of being mm/dd/year when using French it should be dd/mm/year

[CarliJoy]

Or change it to the ISO Date format YYYY-MM-DD

It's ISO for a reason.
mm/dd/year is only used in US, Ghana and Kenya. The rest of the world uses either YYYY-MM-DD or DD-MM-YYYY (with - or .)

See https://en.wikipedia.org/wiki/List_of_date_formats_by_country

Having MDY is really confusing.

Changing it with language wouldn't help as Britian also uses MDY.
Or we would need to introduce Translation by regions.

I would opt for ISO format to keep it simple.
Or maybe a simple selection (M/D/Y, Y/M/D, D.M.Y) that is saved as cookie?