US and Canada only. The North America manual allows the propane Koda 16 to run from a fixed (house) propane tank with Ooni's DH22 hose and quick connectors, and says the kit "shall be installed by a qualified agency". It warns of a "fire, explosion, and carbon-monoxide hazard". This guide gives no owner method.
Not for UK or EU ovens. Natural gas is a different job: see natural gas conversion.