Custom validation on dynamic fields

Yep, this is something I can add!

Yep, will do!

So I finally got a chance to poke around and in my own code, I do add the filter for custom validation but the priority is set to 20 and accepts two parameters. If you want your validation to take place after DTX, try a higher priority like this:

add_filter("wpcf7_validate_dynamic_number*", 'validate_dynamic_number', 30, 2); // Default is 10, DTX priority is 20

/**
 * Custom DTX Number Validation
 *
 * Frontend validation for DTX number fields
 *
 * @param WPCF7_Validation $result the current validation result object
 * @param WPCF7_FormTag $tag the current form tag being filtered for validation
 *
 * @return WPCF7_Validation a possibly modified validation result object
 */
function validate_dynamic_number($result, $tag) {
    // Do something
}

Let me know if that works!

No, I mean using the hook you tried earlier should work if you set the priority to be something higher than 20