To fix this issue, you need to set the value 0 or False for the parameter "longpolling_port" in your config file:
longpolling_port = False
This solution is checked and it works.
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Hi Haresh Kansara,
This is because of the longpolling_port option used in the default odoorc file or odoo config file. The longpolling-port is a deprecated in odoo16.
Please replace 'longpolling_port' by 'gevent_port' option into your default odoorc file or odoo config file or make it False and the warning will be no more raised.
Please Vote up my answer if it helps you.