In case of violation of the system of protection of files and data on your phone, Ucell mobile application is unavailable for downloading in order to avoid risks of leakage of subscriber's personal data (personal data, movement on personal account, details of bank cards and so on).
If the subscriber's phone is based on the Android operating system, it has Root rights installed that gives full access to the operating system of the smartphone.
If the subscriber's phone is based on the iOS operating system, then Jailbreak is installed due to which the Apple security system is broken.