Created date format in downloaded CSV not suitable for import

Problem/Motivation

Downloading submissions to a CSV file results in the created, completed and changed date format of YYYY-MM-DD HH:MM:SS. This is good for viewing it in various formats but not for importing the submissions, which requires a unix timestamp.

I'm reporting this as a bug report primarily due to this issue: #3172700: Created Date is not importing while importing Webform submission from CSV file →

@jrockowitz:

The created, completed, and updated dates must use a Unix timestamp.

The create the above CSV export for the default Contact form you need to use the "CSV Download" format.

@Amit Dwivedi:

Indeed "CSV Download" did the trick. Now the date is in Unix Timestamp and it's imported as expected.

So this is working as expected.

Unless I'm reading it wrong, this seems to be saying downloading submissions as a CSV file should be enough.

Steps to reproduce

1. Submit the default contact form
2. Go to submissions -> download and download as a CSV file

Proposed resolution

Not sure, maybe have an option to configure date formats for the metadata fields.

Remaining tasks

User interface changes

API changes

Data model changes