The Admor of Sherputz, Moreinu v’Rabeinu HaGaon Shloimala Rosenbaum, shlita, has taught his talmidim always to answer a mazal tov with “IY”H by your simchos.”
We should all be zoiche to greet Moshiach with the Rebbe, shlita, bimhayra v’yameinu amain.