There’s a bug with StepTracker 1.4 related to Game Center. If you either disable Game Center or hit cancel instead of logging in when the app first launches, it will crash every time it tires to connect to game center. I have written a fix for this but it won’t be out until Apple approves 1.5 and I can submit 1.6. Version 1.5 also kind of fixes this issue but in a less direct way. There will be an option in the Settings app to disable Game Center for StepTracker altogether. This should solve the crash issue for those experiencing it with 1.4. I have my fingers crossed that Apple might approve 1.4 sooner rather than later.