mbed-os/connectivity/FEATURE_BLE/source/generic/mbed_lib.json

{
    "name": "ble-api-implementation",
    "config": {
        "max-characteristic-authorisation-count": {
            "help": "Maximum count of characteristics that can be stored for authorisation purposes.",
            "value": 20
        },
        "max-cccd-count": {
            "help": "Client characteristic configuration descriptors settings.",
            "value": 20
        }
    }
}