IMEI is the primary identifier to be used for license activation. However there are cases when IMEI is not available, like e.g. tablets without SIM.
Our navigation provides also alternative identification to be used for licensing such as Android ID and MAC address. But please note that MAC address cannot be used since the Android version 5.0.
Another option of licensing is email. If you collect the list of emails of your drivers, it is possible to pre-activate the licenses on emails. Then each driver can activate a license with a first login into navigation. Alternatively you can login a driver remotely with the URL call