My server no longer works for other people.

So a couple of days ago I made a server for the snapshot 13w35b, so I could play with my friends, because I made a mini game. It worked great, but today, when I updated the server to 15w35e (I just copied the world, downloaded the new server and replaced the world with the other one), my friends couldn't join, but I could. The IP didn't change or anything the server just kept pinging and would eventually say that they couldn't connect. The application I use for my friends to play on it (I think, I only watched a Youtube tutorial) is Port Map. I use the smaller, lighter IP at the top that says "Port Map on....", but my friends use the big bold IP that worked before. None of the IP's I gave them worked. I don't know what the problem is.