Beta VoLTE on the Xperia 10 III, disabled by default

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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@jameson, I am talking about middleware between Sailfish and underlying Android stack. Fact that Android stack is using BLOBs and works with the SoC. However, something on SFOS side has to communicate with it. And that communication bits are written by Jolla and closed-source. Which is rather obscure choice for “open” OS :slight_smile:

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Sorry, I understood you were talking about vendor-specific packages.

That middleware, according to Jolla’s description, is also vendor-specific :frowning:

I mean, provided by the vendor rather than developed by Jolla.

Thanks for looking into the Italian providers in so much detail @jameson.

It would be super-helpful if you could please create a separate report in the bug reports category about this, if you didn’t already. It can then act as a place to share ideas, in case there are other users in Italy who have suggestions for getting it working.

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Done, the report can be found here.

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Several reports of losing data service (perhaps after Wifi enabled) despite continued 4G VoLTE connectivity. If others experience this problem please contribute info in the bug report here or share solutions/workarounds in discussion here.

Well. It is.
Jolla, why can’t you make both sims work in 4g?

Have you considered it might be a hardware limitation?

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I would have, if it was 2019.