Final answer:
The question inquires about the engine model year that trucks must have by January 2023, which relates to transportation or environmental regulation compliance. Because detailed context (like country or specific regulation) is not provided, one would need to refer to current policies from regulatory authorities to determine the correct engine model year requirement for trucks.
Step-by-step explanation:
The question is asking about regulatory compliance requirements for trucks, specifically the model year of the engine that trucks must have as of January 2023. Regulations such as these are often implemented to address environmental concerns, safety standards, or technological advancements.
Without access to current regulations or the exact context such as a specific country or region where these regulations apply, it is not possible to provide an accurate answer to this question. Typically, these sorts of mandates are established by government agencies responsible for transportation or environmental protection. It's important to consult the appropriate local or national regulatory authority's website or official publications for the most current information.
For the purposes of this hypothetical response, if the regulation indeed required that all trucks need to have an engine from a specific year or newer, one would need to confirm the latest requirements from the relevant authorities or legal texts prior to providing a definitive answer.