Beta VoLTE on the Xperia 10 III, disabled by default

I don’t know the answer I’m afraid, I’ll try to find out and let you know. However my understanding is that different devices require different VoLTE implementations, so the question is more complicated than it sounds.

In case you don’t get an answer here, I’d suggest keeping an eye on the provider list in case something shows up there (nothing for the US yet I’m afraid).

My understanding is that the packages are device-specific, so they wouldn’t work I’m afraid.

Thanks for highlighting this, but your message will get a bit drowned out here. We’re always looking to make the instructions easier, so if there’s some improvements to be made, would you mind creating a separate thread to discuss it further, or ping me privately so I can get the full details?


Works perfectly in the UK :slight_smile:


Great! Please add your provide to the wiki if you’ve not already!

Where is VoLTE in the user interface?

This is the VoLTE Status Checker app from


Seems sometimes i’m not able to use mobile date while VoLTE is enabled, anyone else experiences this behaviour?


I don’t have access to the internet using mobile data when restarting the phone. Disabling and enabling VoLTE fixes this. Have to check how it is after calls, airplane mode etc.

When I’m using VOLTE I hear no ringtone during call. It connects very fast but silently.
Is this issue known?

Ringtone is a bit of a problematic term since it has a more common use…
You mean the ringing tone or ringback tone, right? In that case i have the same thing.

Yes, the ringing tone…

I am just curious, if the implementation will become open source? I only found from one year ago - is this actually used?
(I am mainly interested because I am myself a SIP developer)

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I’m guessing no - it is not installed on my 10 III. Wonder what is used then…

I would guess, that it utilizes the Qualcomm IMS Android blobs (and by doing so maybe a lot of IMS on the Modem). Which could also explain the very fast implementation and the already very high implementation quality, as I think a total re-implementation of the Protocol in a SW stack would have needed much more time and resources.

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Looks like it is using packages modem_auto_config and ofono-vendor-qti-radio-plugin. Those with 10 III, check what are the corresponding licenses using zypper licenses, for example. That would print out all of them, not sure how to restrict to a single package.

Reference: patterns: Add VoLTE enablers to adaptation pattern. · mer-hybris/droid-config-sony-lena@0676b68 · GitHub


In case it helps: @cyberlyra has now added a row for T-Mobile US to the VoLTE provider wiki (see also their related comment on a separate thread).


Here we go again: VoLTE support packages - modem_auto_config and ofono-vendor-qti-radio-plugin - have proprietary license slapped upon them. Instead of publishing the source code and let us join in the work on getting VoLTE support for SailfishOS, Jolla preferred to choose proprietary license. Nobody has given VoLTE implementation details. It is rather telling when on request to get the blogpost with the details, we get a reply

To request regarding source code on #sailfishos-porters channel - that’s a channel we use for communication regarding porting efforts - we get silence and same goes regarding some questions on implementation. As far as I can see, Jolla developers are afraid to give any reply in public. Which I guess is due to heavy instructions from Jolla’s management.

With VoLTE it does matter. If we cannot dig into the code then, what was above stated as device-dependent implementation, all ported devices will be out. Taking into account that VoLTE importance will only increase, it is a major blow.

By making VoLTE implementation proprietary, we also increase closed-source vital parts in our devices. Which is a norm in most of the recent extensions that Jolla has provided. That includes fingerprint and encryption support.

Quiz question: do you remember any new functionality introduced in the last few years which would be open source? To make it interesting - please list only if Jolla was principal developer behind the project and not forking a project with open source license. I must say that I am not aware of any such advancements.

I do wonder whether such license will stay and we are going to get one more vital black block on the device? Will add the corresponding question to the meeting, at least to get some clarity.


I will do my best to get a clear answer for you.

I suppose the obvious one that springs to mind for me is the Amber Web Authorization framework.


VoLTE is the 4G version of what in 2G and 3G are voice calls. They are fully managed by the SoC. Why should anybody have expected anything different for VoLTE? Is there any device in the world which is using VoLTE on a fully open-source stack which only relies on 4G data?


Meanwhile, while I expected VoLTE to have been fully operational in Italy for a long time, I just discovered that, out of the four Italian mobile operators:

  • Iliad does not support VoLTE altogether.
  • Vodafone does not have any Sony phone in supported models.
  • WindTre only supports the Sony Xperia 5 II (why just that, I don’t know).
  • I cannot find a list of supported devices for Tim, but its low cost brand Kena Mobile does not have any Sony terminal in the supported ones.

Therefore, it is currently impossible to use VoLTE in Italy on a Sailfish device.

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