I would normally recommend keeping the Navisworks version the same as the Revit version. While any collaboration issues will be minimal, it's easier for the users to remember: "2017 versions on Project BlahBlahblah, 2018 versions on Project YaddaYadaa". If you are collaborating with others who have 2018 or later Navisworks they shouldn't have any problems reading the older format NWC/NWD files either.
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If you are going to fly by the seat of your pants, expect friction burns.
"I don't know" is the beginning of knowledge, not the end.