VoLTE on Unbranded Lumia 950XL DS

[T Moore]

T-Mobile in the Czech Republic supports VoLTE on Windows phones with their SIM and update that installs.

Link to their VoLTE information. I can not provide a translated page because it is secure https.
https://www.t-mobile.cz/volte They support the Microsoft Lumia550, 640 LTE, 650, 950, 950 XL directly from their SIM and uupdate that installs with it.

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This is an unbranded 640 LTE. Link in this forum from a user that used T-Mobile in Czech Republic SIM and was mad about the update that installed and changed his phone. He did not understand he was getting VoLTE.
https://answers.microsoft.com/en-us/mobiledevices/forum/mdlumia-mdupdate/unbranded-lumia-640-lte-wp-81-and-wp-10-problem/30e21aa1-e814-4ae7-b6ff-dc2f2ef144fc

 

[nate0]

@T Moore
Ya T-Mobile has come a long way in a short amount of time. I considered moving to their network multiple times, but still band 12 for LTE in my area is still being built out and limited by the TV frequencies in the area that still use some of the block. The good part though is that AT&T is interoperable with LTE band 12, so I get the best of both worlds when I need to using an unlocked phone that has bands 12, 17, 29, or 30.

 

[Kiran R]

I believe I am able to get Enhanced 4G LTE to work on AT&T and the trick is getting access to the device's file system. It is easier though to do this for AT&T service (until they change how it is done) since there is the carrier branded Lumia 950 to pull the modem or other configuration files from. VoWiFi was never a feature (as far as I know) for windows phones on AT&T. HD voice or other enhanced LTE features is all I have seen work on the newer devices for AT&T. I first enabled this feature while using the Unlocked IDOL4s and since I found the ability to do it, I went on to try the 950 XL Dual sim. I had issues initially since the Lumia series are much different than other oem phones in how files are used across the OS. However the major issue was merely an issue with my sim card. I since fixed that and tonight got my hands on another 950 XL. I enabled the IMS Registration toggle and made sure the LTE bands for AT&T provisioned. The only test that I have done so far is to call my voice mail with the WiFi off to see if it dropped to 4G. It did staying on LTE and at the moment am going through all the OS updates until CU. Once updated I will hard reset the phone to see if IMS/VoLTE persist after setup. If anyone is interested in more details for how this can be done on AT&T only, I can paste a link to an XDA thread I used to discuss the process.

Update: HD voice works between other AT&T devices. Now that carriers are moving more towards Unlimited Data plans, and they have the capacity to do it, it makes sense that more and more phones should eventually support these types of features out of the box.

Hi, can you please post the details / link.
Thanks,

 

[nate0]

Hi, can you please post the details / link.
Thanks,

Sorry I am late on this. I created a how to on xda here. Thanks.

 

[farhanaxiq]

Same here, it require carrier firmware (like access point config). Here, iphone and android recieve volte and WiFi calling(even unlocked one) and not my lumia because the firmware was never push to my phone.

 

[PuckCowboy]

Sorry I am late on this. I created a how to on xda here. Thanks.

Hey Nate W! Thanks for posting this! Do you know if this can be done on the single sim 950 XL also?

Thanks!

 

[nate0]

Hey Nate W! Thanks for posting this! Do you know if this can be done on the single sim 950 XL also?

Thanks!

Ya it should work. here is the thread.