Format Submission date

Hello KoBo Team
I need to format the submission data in dd/mm/yyyy.
I tried with the same calculation trick used for other date

calculation = format-date(${my_date}, “%d-%m-%Y”)

As shown in the image, I replaced my_date with _submission_time, but when deploy the project I receive this error:

Unexpected KoBoCAT error 400: b’{“detail”:“There has been a problem trying to replace ${_submission_time} with the XPath to the survey element named ‘_submission_time’. There is no survey element with this name.”}’

Does this method can be appplied also for this “bult-in” field (like submission or start or end)?
Is there an alternative method?

Welcome back to the community, @valerioabbattista! Kindly please be informed that _submission_time is the server’s date and time once a submission reaches the server. Hence, please be informed that you may have to modify the same manually by downloading your data.