I received a similar email from ResearchGate a couple of weeks ago. All I did was respond to the required update, and everything was set! I believe it was an authentic message.
Thank you very much! I guess you are right. I saw later that the address of origin was the same as in their other emails. Should have checked that at once. Strange that the layout of the message differed significantly from the usual emails. Again, great thanks for your message - haven't got any response from the company.