Added on May 14, 2016:
I know this app hasnt been updated for a year now (all I remember is that the last update was in 2015) but I think the TouchID should be enabled for in-app password. Also, its great that I can turn off items in settings like "temperature" for example, but even when I do, temperature is the first thing that pops up when I go in to the graph. I use this app to track my weight, and saw in many reviews that many others do, so I just wish when I turn off temperature, I can make it go away in the graph as well. But other than that, great app - simple, intuitive and as accurate as an app can be.
Okay I was using the free version for several years, and I finally got sick of the ads that made the free version literally unusable- so I bought this paid version. For some reason when I have music on speaker and open this app, the music stops. Maybe this app accesses the speaker for no reason? Annoying! Other than that, its simple its accurate - what else do you need in a period tracker?