The app is called statusmodifier it adds seconds to the status bar as well as ram, either can be turned off with the other functioning, but with both on you lose the lte symbol because there is just to much goin on up there (unless you use zeppelin and remove the carrier). It works just fine on the 5s (I am currently using it on mine)
One thing I have noticed is that I have 2 different apps and they tell me that I have different amounts of ram (they are off by like 200mbps). The first is this app and the other is sbpoweralert.... Not sure which one is correct