HIKVISION DS-2CD51C5G0-IZS User Manual page 186

application is free of use and you need not to import a license key, inactive means
you should import a license key before using the application.
Note:
Before you import the application package, make sure the following requirements are
met.
 The imported applications cannot have the same name.
 The flash memory size of the imported application should be less than the free
flash memory of the device.
 The memory size of the imported application should be less than the free memory
of the device.
Network Camera User Manual
Import License
185