I might’ve found a match with mcfg_sw/generic/euro/emt/vl/est/mcfg_sw.mbn (Telia used to be EMT here originally, and this seems to be the only Estonian configuration available) but even after making a new S252.1/modem.conf with it and rebooting, VoLTE registration does not succeed yet.
I’d leave that running for a while, and maybe see if there’s anything you can request with your provider before abandoning it. Maybe it’ll suddenly start working tomorrow. Thanks for trying anyway though, I think we might get a few people having successes with this.
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Hi Abranson
I am on uk Ee.
I get S20.1
Appreciate you looking at this.
Jon
You are all right. I did a test call with loudspeaker, what i usually not do and spottet it switches from 4G to 2G for the call and back to 4G after it! I can live with it right now, thanks for your answer!
Here are config files for Czech Vodafone: https://github.com/sonyxperiadev/device-sony-common/pull/891 VoLTE is working now, thank you!
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Fantastic that someone’s had some success! I made a topic for this with more explanation of the process. Have fun and don’t break your phones (or you can keep both halves)!
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Yes GSM may stay online till… 2030? Don’t know for sure, but there are just to many GSM-based M2M products in the wild that it’s highly unlikely to be phased out much earlier if at all IMHO.
However, not having VoLTE available is still annoying since simultaneous data and voice connections are not possible in 2/2.5G (or, to be more precise, not supported by any provider in Germany).
Just my 2 cents.
I found AT&T’s USA VoLTE hardware whitelist on their website with all the phones, tablets, etc., that work on the network after the 2g/3g sunset earlier this year. Notably, it includes the Xperia 10 and Xperia 10 plus (with recent s/w update) but not the 10 II or 10 III. So I guess that when I tested out my 10 II with Android in Spring of 2021 before flashing SFOS, it must have been still falling back to 3g when I did the test call. I certainly didn’t think to test that at the time. 
Here’s the doc if anyone’s interested.
Since others have had success with the Xperia 10 II on T-Mo USA, and Big Magenta’s IMEI checker liked my 10 II, I’ve ordered a SIM from them and hopefully can report my findings – hopefully success – next week.
To extend this behavior: I don’t have 2G reception in my office (only 4G). It is eventually possible to receive calls in my office now, but trying to call someone fails, the phone does not even try 4G outbound calls if there is no 2G available. Calls started on 2G do also not switch to 4G when 2G reception fades, as it seems.
Is it possible (for testing) to enforce 4G VoLTE outbound calls through a terminal command?
Not having Mobile Data Connection while taking a mobile call isn´t that dramatic for me.
It was almost anoying for me since I’m using Waze for navigation and an android streaming app for audio pretty often, and these app requested a restart each time the dara connection broke. Plus you wouldn’t get updates in Waze (speedcams, traffic) if you were making calls while driving which could thus become very expensive either in time or money:-)
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In general i agree you that this should be fixed, even for the older Models. In the meantime i use offline Navigation with Here We Go or OSM-Scout.
Btw. good Navigation-Software should precache and load all static content when starting the trip.
I tried to activate VoLTE in Xperia 10 ii but failed. Country=Finland, Operator=Moi, Network=DNA. It appears DNA network supports VoLTE but Moi does not (just asked them). To me that is not really important because Signal and WhatsApp calls.
Spusu/Mass dont provide VoLTE, I called the company to ask about it.
Outgoing works, but not incoming. Using Ice and an Xperia 10 II in Norway.
- Country: NO
- Provider: Ice
- Device Model: 10 II
- Date tested: 2022-07-18
- Registered: ✓
- Voice In: ✕*
- Voice Out: ✓
- SMS in: ✓
- SMS out: ✓
*Sailfish phone disconnects from LTE when call arrives, caller gets a busy tone as if I hung up immediately, phone then reconnects to LTE after about 2-3 minutes
This is possibly caused by Ice doing network switching. Between their own network for LTE and Telia’s for 2G/3G. When it receives a call the phone probably still tries to switch to 2G/3G, even if that shouldn’t be required. How this switch works I’m not sure, maybe it’s a lower-level SIM/Modem thing.
When checking Ice’s list of supported VoLTE phones I notice that the Xperia 10 and Xperia 10 III are listed, but not the Xperia 10 II. It’s possible Ice as a carrier specifically does not support the 10 II, for whatever reason:
Unfortunately I don’t have the ability to reflash the 10 II with Android atm as it’s my daily driver.
Works as a charm, without any need for reboot:
Country: NO
Provider: Phonero (Telia)
Device model: 10 II (XQ-AU52)
Registered: ✓
Voice in: ✓
Voice out: ✓
SMS in: ✓
SMS out: ✓
EDIT: I saw now that I could edit the list in the OP directly, and I have filled in the data there.
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I tested Iliad in Italy on my 10 II XQ-AU52, using the new toggle in 4.0.0.68, and I cannot get it to register.
EDIT: it seems Iliad does not offer VoLTE yet, even for Android devices.
T-Mobile Poland. I have so called “Tandem” SIM cards (twin SIM cards that one can insert into two devices and use interchangeably) and I’ve just been told by T-Mobile customer support that they do not activate VoLTE and VoWiFi services for those cards. The only solution is to change those Tandem cards to a normal single SIM card, which is what I am not going to do anytime soon because I very much enjoy the freedom of being able to switch easily switch between two phones without having to swap the cards. So no VoLTE or WoWiFi for me in the nearest future.
P.S. This must be some “political” decision without any real technical background, because on various forums there are reports from people having those Tandem cards who somehow managed to have VoLTE and VoWiFi activated on them. To me, the customer support person told “I’m sorry, I really cannot do this”, which sounded more like “Sorry, I am not allowed to do this” rather than that it is not possible technically. I’ve asked him if they still offer those Tandem cards and he confirmed that they are still being normally offered, which means that they sell a product/service which is incompatible with other services of theirs.
Knowing how some call-centers operate it may help to call them a few times asking the very same question until someone activates this for you not knowing he/she is not supposed to do that 
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Yeah, I’ve already tried twice, no luck so far. But I’ll keep trying. I also used to have a couple of friends working in local T-Mobile shops, so it might be a good idea to check if they’re still working there. I’ve learned that T-Mobile Poland now started offering so called eSIM’s (for a monthly fee), so this is probably the only reason why they’re blocking the Tandem service (which was free of charge) from having VoLTE activated.
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