Well, there appear to be not only implemantations on the hardware site, but also on the software site already present on the Sailfish release for the Gemini PDA, including init scripts and binaries.
It’s possible to invoke those manually (without any effect or output to the command line, though). Probably difficult to utilize those without any documentation, but I guess it’s save to say they are already there (and don’t segfault when invoked).
However, I guess it is probably a better solution to integrate VoLTE through the SIP integration rather to a standalone app, but still it may be possible in an app (which needs to integrate deeply in the system, e.g. to disable 2G/3G fallback for voice calls).
I guess the libs and bins mentioned above are device specific, since they are not present on sfos on my xperia. Therefore currently only an option to play around with those on a Gemini PDA (or other MTK devices with sfos, if there are any).
Overview about the VoLTE related files:
I would not say it can’t be done but I guess I just take the lazy route and use plain old SIP with a data-only SIM card.
Sure your App is great in either case!
However, I’d personally prefer VoLTE since I have an unlimited plan, plus I’m often traveling to rural sites with poor 2G only coverage. SIP is not an option there. To make it worse, my provider seems to have switched some sites from 2G only to 4G only, leaving me unable to make calls at all (except for e.g. Whatsapp or SIP).
I guess the need for VoLTE is already there and it’s getting urgent…
While I fail to understand why VoLTE should work where SIP would not be an option I don’t mean it would not be nice for Jolla to implement VoLTE, just that I would not hold my breath.
No. In 2G networks, I can do plain old CSD calls (and SIP is not really an option even in 2,5G (EDGE) networks. When moving into the next cell, let it be 4G only, the call would be cut off without VoLTE. I could, of course, use SIP then (with a different number though), but once I leave the 4G cell again into another 2G cell the call would be cut off again, and I’d have to redial through CSD. This szenario is not that seldom particularly when driving by car.
That’s, of course, as long as 2G and 3G are still around. I don’t want to claim for it to be a solution for everyone but what I’ve been doing for years was to just use my SIP number for basically everything and forward the call to 2g/3g in case the SIP client was not reachable. It was still not ideal (means manually rejecting SIP calls on 2G where SIP would still work but RTP wouldn’t) but, well, it was the era of people getting ripped off by inflated roaming charges so this was something that paid itself off rather quickly. Right now I don’t even bother forwarding calls any more because of the excellent 3G/4G + wifi coverage pretty much wherever I go. Also the number of voice calls I receive seems to have decreased significantly over the years with most of them being telemarketers anyway.
…they better find a way to undelete it if they don’t want to see their operating system reach the end of life in early 2022 as carriers force everyone onto VoLTE.
In Russia? That’s where it counts.
I watched the stream earlier of the Ubuntu Touch Q&A 82, and the first topic to be discussed was the collaboration of UBPorts, Jolla, and Sony to get VoLTE working on the Sony open devices. While I wish there was more information conveyed, it at least indicated that the work is happening, even if it’s going to take time.
Considering SFOS is open source. Are there any developers who can create a ‘patch’ for VoLTE, or is this part of the proprietary bits, or just too difficult to implement? Sorry speaking as a complete layman on the matter.
Are there any other alternatives to SFOS if VoLTE is not implemented within a few months (by 2021)?
While there are some bugs and quirks, I do like SFOS, and it does continue to improve with each build. So it would be kind of sad for me to leave it, and sad for them to lose all of us - essentially Beta testers who bought their OS.
no ‘patch’ is possible, yes VoLTE/IMS is implemented in proprietary firmware (e.g.: in modem.bin) and requires support from Sony
alternatives to SFOS include burying your phone in the dark of night, setting your phone on fire, or launching it into space on a trajectory that will carry it out of the solar system.
though i also hear LOS 17.1 works with VoLTE on the XA2, so it doesnt seem totally hopeless
The situation is not as hopeless as @teleshoes seems to let you understand 
There is nothing on the baseband side that you don’t already have in the firmware of your Sony device, it is just putting the pieces together in the driver software (ofono)
I guess I will buy myself a data-only SIM should they really start banning non-VoLTE phones in 2021
@maajussi considering this issue will impact a potentially large portion of Jolla’s user-base in the coming months, is there something the community can do to help Jolla make this development a priority?
Can the community assist in terms of time or money, other resources to help in developing this feature?
Can this be rolled out in the next build being worked on (whatever the next one after the soon to be released 3.4 would be)?
If successful, this may be a good step in improving the somewhat strained relations with the community and developing some goodwill as you guys are looking to do.
From Summer 2021, 3G (UMTS) will be turned off by Telekom Germany. So: VoLTE would be highly appreciated by the german users.
Vodafone will switch off at the same time, so only O2 (Telefonica) will remain (for some time) for the German Sailfish users.
The fall back system would be 2G for telephony, so we won’t have to switch to O2, just to get stuff working. It’s just, that later 2G will be switched off. Until then, VoLTE needs to be established. And the Pinephone will be a perfect solution to this question. A community Version and perhaps original Sailfish would come in very handy!
Why should we switch to O2? When they switch off 3G we can still use 4G.
3G contracts will be upgraded to 4G. Same announced Vodafone.
Telekom nennt Termin für 3G-Abschaltung
Is that not the actual problem? 2G is telephony, 3G telephony + data, 4 G only data. And for using the data stream we need VoLTE. So Jolla has to implement VoLTE these days, if they don’t want their community and business partners being not able to phone. But i see it like others, unless the Brics states are asking for it, Jolla will not move…