The longpolling-port option has been deprecated in Odoo 16.0 and you need to change it in  the default odoorc file or odoo config to gevent_port

or you can set the value to False:

longpolling_port = False

It functions with the current date.

How can I get the duration based on the date and time?

for myself:

if both i.start_date and i.end_date exist:

Datetime.strptime(str(i.start_date), "%Y-%m-%d %H:%M:%S").date(); s_date = datetime.strptime()

Datetime.strptime(str(i.end_date), "%Y-%m-%d %H:%M:%S").date() yields e_date.

If the date is smaller than the e-date, then

(e_date - s_date) is the outcome.

i.duration = outcome

alternatively:

message = f"{s_date} Needs to be preceding {e_date}."

message = raise UserError

Not working for me, in v 15 worked fine, now the chat option is useless, very sad