Apps that have been modified with tweaks —called Exos in Extensify language— contain a ‘+’ sign after them for easy identification. So, for instance, if you modify YouTube with the Cercube Exo, the YouTube app will be deployed to your Homescreen with an icon called YouTube+. It’s not possible to have two of the same apps installed at once—one.
If Extensify app is crashing, Visit install page using Safari on your iOS device and login with your account to reinstall Extensify. If Exos are crashing, open the Extensify app and go to My Exos section and rebuild/reinstall your exos.
Once you install the app using Extensify, you won't be able to update it through the AppStore. Instead, to make sure it'll stay compatible with the exo version you're running, you'll be able to update it using the Extensify app when an update is available and is compatible with the exos installed.