About a year ago Tim B has announced the introduction of the DeviceTimeReq MAC message. This MAC message is introduced in LoRaWan since version 1.0.3. And the KPN network is using 1.0.3 to my best knowledge, so it should support said MAC command.
And sometimes it does!.
I have tried using the DeviceTimeReq (0x0D) mac command. Once in a while I get the expected DeviceTimeAns (0x0D) reply back, but very often the network does not send a reply. Perhaps only 1 out of 6 times it works as expected.
But when it does work, I get an accurate network time
So, why does it only works sometimes?
Some details: my class C node is ADR connected and ran on SF9 during the experiments. The reported SNR and RSSI for application messages are well within the norm and upstream messages almost never get lost. I send the DeviceTimeReq MAC message as FRMPayload on port 0.