From what I understand, they switched streaming hosts and/or providers and are required to use that provider's apps. If you visit the listen live page and save it to your homescreen, it will work like a single station app.
If you're like me and hate single station apps with a passion, you can get the "pro" edition of TuneIn and add the station's link manually. I've had the pro edition since before TuneIn offered a free edition, and found adding it extremely easy. That page doesn't hide streaming links very well, and you can find the stream easily if you know how to inspect elements and view page sources.
On my iPhone, if you're not on TuneIn, iHeartRadio, RadioPup or Radio.com, you don't even get a glance, let alone a listen. I also only bring up TuneIn and iHeartRadio at work. So, again, unless you're on those, you don't get a listen. I have all the ones I have on my iPhone on my iPad except RadioPup. So, I have some of the Townsquare stations and other favorites, like 103.7 The Oasis, manually put into TuneIn so I can listen to them on the iPad or at work.