Bug Report: F8131 Calling Issue

[Pergatory]

I just wanted to put this out there and make the issue known so hopefully a software update can possibly address this properly.

I found a strange issue where it appears when the phone receives a call while connected to a wifi network, that it tries to pick up the call on wifi instead of properly handling it on the cellular network. The carrier I'm using is T-Mobile USA. My speculation is that wifi calling isn't properly disabled and the issue occurs. Generally what will happen is someone will make a call, and the call will ring twice and then to straight to voicemail. If the phone is taken off of wifi, or an outbound call is successfully made while on wifi, the issue disappears temporarily (somewhere between 8 and 16 hours. I'm assuming when a change in network occurs). If the phone is rebooted with wifi on, the issue is then easily replicated as calls won't successfully make it to the phone until wifi is disabled or an outbound call is completed.

[CameronT]

Hi @Pergatory,

Welcome to the community. 

WiFi calling is a network feature rather than a phone feature. Have you contacted T-Mobile about this?

I also recommend you contact your local Sony support team to note the issue.

[Pergatory]

I'm inclined to believe it's not necessarily a problem with the network, as there are no wifi calling settings applicable in this version of the firmware. The reason I believe it's a problem with how the phone is handling things, is for one, I've observed this exact issue on two different phones wirh two different sims, within the same network. Two, whenever a call is incoming, the phone shows wifi activity, and then stops when the call is forwarded to voice mail, however the phone is connected to the cellular network at the same time. And it's worth noting that both phones do not support wifi calling at this time, as there is no configuration for it, and T-Mobile traditionally has to install their own software for wifi calling.

[Uliwooly]

@Pergatory

Simple, T-mobile doesn't have this phone, which means that you are using a SIM free phone, this won't work, the phone has to be network branded. 

[Pergatory]

I'm aware this is the case, however I find it most peculiar that wifi would interact with calling in such a way, even though this setting doesn't exist. I've shot an email over to the Xperia Support Team, and we will have to see what they have to say on the matter.

[Uliwooly]

@Pergatory

Interesting, keep us updated. 

[CameronT]

@Pergatory,

I wonder... Have you previously had a phone that did support WiFi calling? And if so, did you have that function active?

[Pergatory]

Yes, my old Xperia Z3 supported it, however I haven't had the feature enabled in at least several months because the feature turned out to be more of a nuisance than anything else. I did a sanity check to make sure a couple of days ago when the thought of it being a Wifi Calling issue occurred to me and verified that it is in fact disabled. 

[CameronT]

@Pergatory,

I see. Would it be possible for you to test this on a SIM from another network?

[Pergatory]

Not currently at this time, but I will keep my eyes out for someone's SIM to st-... appropriate/borrow. :3