Sniff, sniff

I guess my baby is growing up - Jacob has outgrown the "newborn" diapers! He actually outgrew them a few days ago, but we still had a bunch of them, so we kept on using them. He had a little bit of the plumber's butt going on, but overall they were ok. However, I just used the last "newborn" diaper. Does this mean that he is no longer a newborn?