Identity Portal can be used across regions and countries, each has its own language and format for the calendar UI.
How is this determined?
Identity Portal 14.3
Starting from version 14.3 the determination of how the calendar UI will look like is determined by three options.
If there is a language selected for the user. It takes precedence.
If there is no language selected then the calendar UI is displayed according to the browser locale.
If no specific browser locale is defined, the calendar format is displayed according to the machine locale.