Description

When validating structured data generated by Joomla (tested on https://cloud-planet.uk/queen-of-diamonds-tattoo-studio), I noticed that the dateCreated and dateModified fields are not formatted according to the schema.org recommended ISO 8601 standard.

This causes non-critical warnings in tools like:

• Google Rich Results Test
• Schema Markup Validator

Steps to reproduce the issue

1. Create or edit an article in Joomla.
2. Enable structured data output using the Schema tab on the standard create article screen.
3. Choose any schema type that has a date field in the form (I used 'Article').
4. Use the built-in date picker to choose either a 'Date Created' or 'Date Modified' or both.
5. Validate the page using a structured data testing tool.
6. Observe the date format warnings.

Expected result

The Date Created and Date Modified fields when filling out the Article schema (and I'm assuming others) should save the dates in ISO 8601 standard.

Actual result

The dates are stored in a non-compliant format.

System information (as much as possible)

Joomla version: 5.3.1
Template or plugin used: [Insert if applicable]
PHP version: [Insert if known]

Additional comments

Suggested Fix: Ensure that all date fields in structured data output use the ISO 8601 format (YYYY-MM-DDTHH:MM:SS+00:00), which is required for schema.org compliance.