Change or upgrade the bluetooth security level

[Prashaanth06]

Currently I am using bluez 5.55 version and I have developed a gatt server for read, write and notify and things are working as expected, able to send and receive data. When I checked for the security level of bluetooth I got to know that it is falling back to security mode 1 and level 1(got to know after performing bluetooth sniffing using nrf52840 dongle) which has no encryption and authentication.

I am using Just works pairing mechanism so my aim is to atleast move to security mode 1 and level 2(encryption: yes and authentication: No) I checked in the main.conf file of bluez 5.55 I dont have any properties related to security so, I tried to move to bluez 5.78 which is the latest and tried setting this property SecureConnection = on and SecureConnection = only then restarted the bluetooth daemon,

Logs after the change:
bluetoothd[1269]: Bluetooth daemon 5.78
bluetoothd[1269]: src/main.c:check_config() Unknown group AVRCP in /etc/bluetooth/main.conf
bluetoothd[1269]: src/main.c:parse_config() parsing /etc/bluetooth/main.conf
bluetoothd[1269]: src/main.c:parse_config_string() General.SecureConnections = only
bluetoothd[1269]: src/adapter.c:adapter_init() sending read version command
bluetoothd[1269]: Starting SDP server

In logs I could see that the secureconnections properties is configured to only and I am using bluez 5.78 but still I see it's in security level 1. How to upgrade to security level2 ?

I am checking the security level when it's pairing with a nomadic device. I am pretty sure that the nomadic device also supports secured connections. Am I missing something how do I approach to upgrade to security level 2?

[Prashaanth06]

@Vudentz could you please help me here?