I would like to ask if you know any methods of storing an information that an application has been installed to a device. In my scenario, the application can be used freely for a period of time but after that time user has to register it. After reinstallation I would like to keep the information that application has been installed (possibly with other data - remaining free period) and not to allow to run it in free mode.
I think of creating a hidded file in file system but it is not very safe. Do you know any better methods? My target devices are 3rd edition FP2