Actually it will depend what frequency bands the device can handles, usually the 4G LTE and LTE Advance which are the provide by TELUS, they will support phones with 2100 MHz, 1900 MHz, 700 MHz, 850 MHz, as far the device you purchasing handles this frequencies, I don't see why the device should not work with TELUS networks, however the device wont be available to purchase with any Canadian phone company as far as I know.
I know what the device can use, hence what I said. The US/Canadian Internation firmware and the T-Mobile US firmware both contain the same radio configuration.
HSDPA 800 / 850 / 900 / 1700(AWS) / 1800 / 1900 / 2100
LTE band 1(2100), 2(1900), 3(1800), 4(1700/2100), 5(850), 7(2600), 8(900), 12(700), 13(700), 17(700), 18(800), 19(800), 20(800), 25(1900), 26(850), 28(700), 29(700), 32(1500), 34(2000), 38(2600), 39(1900), 41(2500), 46, 48, 66(1700/2100), 71(600) - North America
The International firmware, 9.5.7, has fixed a few major issues with the camera. It still isn't anywhere near the DXO mark their prototype with different hardware claims, but it is a lit better than it was at launch. The WiFi to cellular hand off has also been fixed to not require a reboot to hand off from WiFi Calling to cellular and back. The ghost touch issue within certain apps is more of a hardware issue. If anyone runs into that, return their device for a replacement. If your device powers off after heavy use and won't turn back on. You will need to hold the volume up and volume down and plug it in via USB to enter EDL mode and reflash the device. There still isn't an explanation for this issue, but it does seem to be common enough to mention.
Here is a screenshot from my T-Mobile purchased GM1915 that has been converted to the dual-SIM GM1917 firmware. VoLTE works perfectly on Telus! 9.5.8 is the latest firmware available, which I received via OTA last night for the GM1917 firmware. The cameras are still very disappointing but everything else about this device is fantastic!
You have the international model of the phone. I wonder if it's configuration is slightly different than the T-Mobile firmware @Syaoran mentioned?
It can't hurt to try whitelisting it. I swap out devices very regularly though. My Mi MIX 3 works fine with VoLTE as well. Do you have the 9.5.8 firmware on your device yet? There should also be another update coming in the next couple of weeks for the GM1917 firmware.
Yea, I got the 9.5.8 Update and also tried the tips to get VoLTE with *#800# I now see them in the options, but they don't do anything. When I make a call, I jump from 4G+ to H+, so not staying on LTE. I also tried switching my telephony profile with PDC by choose the TMO (T-Mobile) profile, but still no luck with that. I guess I'll have to ask Telus to whitelist the device, my only option left.