VoLTE support in SailfishOS?

In Android there is not no IMS protocol stack for VoLTE, it only has Interfaces to use vendor provided IMS service. Maybe IMS service developed for Android can be used on Sailfish too.

1 Like

One thing that’s kept me from just using my SFOS phone as a wifi hotspot since it got the 4G capability is that it drops the connection to 3G for the duration of a call - and all TCP sessions get cut. That’s extremely annoying. Se even though we’re probably not going to lose 2G networks in Finland anytime soon, the annoyance will be there all the time.


Is the problem there when using UDP VPN session as well?

Nope. And Mosh also works. But sometimes the difference between using a VPN and just a direct connection can be significant if there’s lag somewhere along the way using the VPN but not otherwise.

1 Like

I have disabled 4G from my phone, as 3G has enought bandwidth for my usage. And most of the time it’s connected to WIFI. And 4G eats much more battery. But I need to think what to do after 3G shutdown. Support for VoWIFI (WiFI calling) would be nice, and probably saves battery too. So I hope also to get working support for IMS services on Sailfish.

There was a fix for Android if I’m not mistaken… For Generic images…

I’m with H20 myself (they are an MVNO of AT&T). AT&T are switching off their 3G network in Feb 2022 which will directly affect anyone on a non-VoLTE phone after that point.

It’s not accurate that it’s an FCC mandate but it is accurate that the 3G network that H20 uses will shut down next Feb. My SO is still using a Nexus 5X and has had the SMS message you’ve mentioned. H20 do call it an FCC mandate but that’s not accurate - clicking through the H20 link from the text provides this link to the FCC regarding the issue - note that nowhere in that FCC page does it mention anything about it having mandated carriers to switch off 3g.

The point is that with AT&T deciding to make the switch, H20 have no choice but to do the same as they’re simply reselling service using the AT&T network.

As I mentioned on this thread I don’t have any problem with this not being implemented as it affects a market that Jolla doesn’t serve - legally speaking you can’t buy OS licences from the US and the Sony phones they work on aren’t sold in the US either - the LTE bands they support are very different to the LTE bands AT&T use. From that post, I mentioned that my XA2 supports LTE bands 1-5,7-8,20,38. The main bands AT&T has widespread use of are 12&17, so adding VoLTE support is pointless when my phone can’t connect via the bands it supports as they aren’t the main ones used by AT&T.

Right now the only option seems to be to switch to T-Mobile (or an MVNO that uses T-Mobile) and hope they don’t annonunce a shut-down their in-house 2g&3g network (they’re shutting down the Sprint 2g/3g network next spring) but with AT&T switching in Feb & Verizon in December 2022 I’d assum it’s only a matter of time.

The TLDR version of this post - Sailfish OS is unsupported in the US and even if they add VoLTE support, some, if not all, of the Sony phones supported on Sailfish X were never sold in the US either so don’t have the required LTE bands to work anyway, so adding VoLTE support may well be pointless.

Guess we have to hope that someone makes a phone that Jolla can support that supports the full global range of LTE bands that anyone may need.


I think XA2 model H3123 should have band 12 and 17 support. Other models don’t.
And same applies to Xperia 10 model I3123.

That Android fix is only for phones with Qualcomm chipset. But the 4G Android phones that don’t have Qualcomm chipset is currently minority.

Where did you get the T-mobile hasn’t announced a date or Verizon’s date? I thought I saw one even sooner than AT&T from T-mobile.

It’s in this link to the FCC website that I previously posted.

T-Mobile did announce a date, then retracted it - I believe due rules set by the FTC that allowed the Sprint merger to go ahead. Essentially they were supposed to not switch off 2g/3g so that Dish could have time to build out their own network to become the 4th carrier in the US - that was certainly part of the merger agreement with the FTC.

I assume they’re shutting down Sprint’s 2g/3g network as they’re CDMA, not GSM based - so it’s irrelevant to the vast majority of Sony phones which are all GSM based bar the select few models that Verizon have offered.

T-mobile 3G ends October 1, per: The big T-Mobile and Sprint 2G / 3G shutdowns are coming — and we have new information