I came across a client example that use the
atomic_set_bit( var_bt_gatt_subscribe_params.flags, BT_GATT_SUBSCRIBE_FLAG_VOLATILE );
I read about BT_GATT_SUBSCRIBE_FLAG_VOLATILE
If set, indicates that the subscription is not saved on the GATT server side. Therefore, upon disconnection, the subscription will be automatically removed from the client's subscriptions list and when the client reconnects, it will have to issue a new subscription.
How I know if the subscription is not saved on the GATT server side (which I already developed)?