The above was taken from the web site that explains the entire history of WD-40, up to and including present day. It makes no mention of a change in the formulation. I cannot explain why the WD-40 web site says it contain petroleum. Is fish oil now considered a petroleum product? It is an oil. Is petroleum part of the formula? I don't know. I'm not a chemist. All I know is, the stuff works, and I use it on everything.
I'm just stating what I know. I do not wish anyone to take offence. Ignore this at your pleasure.