Yes, I think it is a protocol version mismatch. I have received the same error with strfry v1.0.1 and I don't think relay.damus.io has upgraded yet.

I've had success with relay.westernbtc.com and several others. 

 I upgraded mine so I doubt it will work anymore. 

 Was testing earlier today with strfry 1.0.1, it works. 

 Awesome!