Unable to update Bluetooth connection parameters

I am trying to update the connection parameters of my BLE connection. My device is in peripheral mode and I am trying to connect to an IOS device. Right after the connection is established I tried to call

void QLowEnergyController::requestConnectionUpdate(const QLowEnergyConnectionParameters &parameters)

I received connection updated signal but the parameters are always the same and there is no update. Here are the values I get

latency : 0
maxinterval : 60
mininterval : 60

I will be thankful if someone can provide some minimal example.