Can you pass datetime data to a date field via API

Do you have an example where this happens?

hubspot_recent_conversion_date_c

I just modified the closed_date of an RLI in version 13.0 with API v11_20 with a timestamp and it worked fine.

rest/v11_20/RevenueLineItems/7c1a703a-15aa-11ee-ba0f-54ee7593936c

{
"name":"changes RLI",
"date_closed":"2023-09-03T16:20:07+02:00"
}

result:

I suspect so - working with them on it (its actually ActOn)