Tell HN: AT&T disabled phone numbers and accounts of users using the old phones

130 points by throwaway0900 ↗ HN
AT&T disabled users phone numbers and account for using SIM in the phones not on the whitelist. https://www.att.com/idpassets/images/support/pdf/Devices-Working-on-ATT-Network.pdf

https://forums.att.com/conversations/wireless-account/my-att-prepaid-account-disconnected-today-but-i-just-added-money-this-sunday/6271d8e6ee9f260c2628029a

98 comments

[ 4.3 ms ] story [ 171 ms ] thread
I think the real reason is shutting down of the 3G network in order to support 5G roll outs and more LTE.

This is a kin to raising arms over the EOL support of Windows Vista.

I had this happen - they're disabling the SIM and associated line, whether or not it's actually being currently used in a 3G device and whether or not the service is currently functional.

When I talked to the AT&T folks in store, they indicated that it was happening even on 4G capable devices that weren't bought from AT&T and therefore were unlisted in the system.

It's simply being used as a driver for new phone purchases.

Verizon also will mark your line as hotlined, disabling all functionality if you use a device that works but they don't like or if your late in payment or trip up another undisclosed trigger.

https://community.verizon.com/t5/Verizon-Wireless-Services/W...

https://www.reddit.com/r/verizon/comments/4oaw2x/i_hotlined_...

I wonder how long I have on T-Mobile, I keep getting texts like "T-Mobile: Action needed. VoLTE settings may be affecting service quality for phones on your account.". On this particular account there is a single Nord N200 5G bought from T-Mobile, and as far as I can tell VoLTE works fine on it.

> used as a driver for new phone purchases

except they sent free phones to people who had 3g phones. They weren't super-new, but they were newer than the phones they were replacing.

I read about the change several months before and migrated from a OnePlus 5 to a Pixel 3a.

I am on an MVNO, so I ultimately decided to migrate back to Verizon. The only reason that I was on AT&T at all was a larger diversity of supported devices. VoLTE has really put an end to that for me, as I'm on LineageOS.

> VoLTE has really put an end to that for me, as I'm on LineageOS.

This is extremely device dependent. Out of officially supported LineageOS models, the general rule of thumb has been VoLTE that works in stock firmware on Motorola or Oneplus will also work in LOS. Samsung won't as they have a proprietary implementation.

AT&T goes a step further than just blocking devices that don't register on IMS and also runs IMEI whitelists so almost all imported phones will not work on their network.

Yup, choice in phones was one of AT&T's only advantages over Verizon (remember when their phone selection was literally the Island Of Misfit Phones?) and that's gone now.
I left AT&T back in 2012 or so when they started to flag and reclassify my plan on every import model I bought. Prior to that, T-Mobile was almost purely urban and AWS band supporting phones were a little obscure. But that's not an issue today and now I can import whatever.

I still have a few active SIM cards supporting GSM-only operation if I feel like using an old phone from 2005. (I have a sony ericsson w810i that Google's WAP site still works on, the oldest phone I tried within past year was a t68i but data wouldn't work, just calls/sms)

I can understand shutting down 3G network, but terminating accounts and phone numbers abruptly is unacceptable. Now SIM card doesn't even work in new phones.
It's worth noting that many cheap android devices let you spoof the IMEI and other device identifiers. If so, just find someone else with the device you want to emulate and copy over the identifiers over. It's usually an app in the app list as "Set up Phone" or something - you type in the IMEI, hit save, and then reboot. Probably best to find someone not on the same network as you - many phone networks won't let two phones with the same IMEI connect at once.

It's very useful in countries like Turkey which don't allow foreign phones. So you need to copy the IMEI of a local unless you want to buy a new phone.

>It's worth noting that many cheap android devices let you spoof the IMEI and other device identifiers.

Any devices this is going to work on will be old and will not support VoLTE. Modern smartphone SoC's (all the Qualcomm ones at least, which make up majority of US android devices) have the modem IMEI stored in memory that can't be modified, any guides on these devices are just about spoofing IMEI reported to android system, not to the network.

Cheap phones are nearly always Mediatek, and those have a debug tool to change the IMEI. I assume the OEM IMEI change functionality uses the same api.
Back in the Android 1.6 days, on many Qualcomm devices you could write all zeros to the IMEI, and then it'd let you write whatever IMEI you wanted. It was supposed to be read only. Carriers were launching new plans for 3G smartphones that were more expensive than the existing unlimited data plans intended for WAP phones. Move the IMEI from your old WAP phone to a new Android phone and you had very cheap unlimited data for a few years.
This is not true. My daughter's phone supported VoLTE but was not on the whitelist and service was terminated based on the IMEI. We had to order her a new (but actually older) phone that was on the approved list in order to reactivate service.
> This is not true.

Which part of what I wrote isn't true? I'm talking about device IMEI spoofing, not AT&T's whitelist.

It is not just "old" or 3G-only phones, it is any phone that is not explicitly on their whitelist.

I have been using a f(x)tec pro1 for years on 4G+VoLTE on their network, and got the same text message saying they would terminate my account if I did not get a different phone. I decided to lay low and moved my sim into a supported phone with the intention of letting the dust settle white I prepare to port my number to t-mobile (they have by far the worse service in my area, but seem to be the only US provider allowing the pro1 to be activated).

I still have an inkling of hope that I will be able to move my sim back to the pro1 after whoever is responsible for the 3G shutdown gets their bonus and they stop going after unsupported devices aggressively.

There must be some sound technical justifications for what AT&T has done, but this extremely hostile to the customer base.

They also retain metadata on users for seven years, longer than any other carrier.

I really should have left long before I did.

https://www.nbcnews.com/technolog/how-long-do-wireless-carri...

ATT, the company with the Death Star as their logo, is hostile to their customer base? Say it is not so...

ATT is the worst company, even worse than comcast. Doing something to just be hostile to their customer base is in their DNA, they are used to their monopoly status from the say of Bell Telephone, that company will never change and will never be customer friendly

This.

Was in the same boat over a year ago when AT&T started SMS spamming about 3G sundown plans on one of my prepaid phones (Blackberry Key2) flagged as "incompatible"; to be sure, the older KEYone and Priv models are apparently whitelisted because AT&T had sold and directly supported those models at some time in the past.

Got so annoyed by the recurring, persistent warnings and no reasonable explanation why this 4G VoLTE phone would be sucking hind tit on their network in the near future that I ported the number to T-Mobile on a random Sunday afternoon (reduced monthly bill too) and never looked back.

If the UX leading up to disconnect was anything like mine, I'm honestly not sure why this event is catching so many AT&T customers off guard.

What do you mean by the "only US provider allowing" ? Blacklisting old phones is a thing every US telcom is doing ? I'm european, I know the US is really NOT into consumer rights, but still, this is a massive FU to phones users who want to keep their phone for a good 2-3 years, and pushes for a massive electronic waste.
It's not blacklisting, it's WHITElisting which is much worse - all the phones not explicitly sold by AT&T or otherwise approved will not work. So you pretty much don't have a free market choice of your device despite it being compatible with the network.
Kickbacks from the "approved" manufacturers to the phone co in return for exclusive access to their market. Yet another revenue stream...

All supporting my growing conviction that phone co's are constitutionally incapable of delivering good internet connectivity and should be forced out of that game as soon as, and by any means possible.

It is almost like we should break them up for such practices.
After they just spent 15 years consolidating into a handful of providers?
> I still have an inkling of hope that I will be able to move my sim back to the pro1 after whoever is responsible for the 3G shutdown gets their bonus

you're missing the point

at&t is shutting down 3g towers because pretty soon they won't be legal anymore

no cell company can service you whether they want to or not. that spectrum is being turned over to 5g devices mid next year.

https://www.wired.com/story/3g-service-sunset-what-it-means/

Also the entire Europe is sunsetting 3G, some networks have already done so and many have announced their planned dates up to 2025. They're calling 4G LTE the much better alternative - from phones to IoT and whatnot.
Really, the strong point there seems that the provider has whitelisted a number of devices that they will accept on their network, and cease contracts when they see different devices around. The OP mentions a «pro1 ... on 4G+VoLTE», another post a «LG V30 (2017)», nearby you will read of a «OnePlus 6... support[ing] 4G and VoLTE»...
>I still have an inkling of hope that I will be able to move my sim back to the pro1 after whoever is responsible for the 3G shutdown gets their bonus and they stop going after unsupported devices aggressively.

ATT is just about one of worst telco company around. It doesn't surprise me they are doing stuff like this for bonus or whatever reasons. They have in the past selectively blocked email, calls before (for their customers without notices) and now phones. If you can do NOT use ATT as a telco provider.

I am using a OnePlus 6, still working perfectly fine, supports 4G and VoLTE ("HD Voice")[+]. AT&T kicked it off their network because it is not on their whitelist (The OnePlus 6T is). They sent me a branded LG Prime 2 as a replacement of a "equivalent" phone. It is actually a budget phone, not supporting 5G, and not even on AT&T's approved devices list (it seems they added it now, but last year it wasn't).

Forum users reported that customer service can whitelist an IMEI. They did not for me. So I switched to the T-Mobile network. From my international SIM now I get a message from their roaming partner AT&T saying that voice calls will not work.

T-Mobile is sunsetting 3G as well in July 2022, they sent me a text saying that they "think" that my phone is compatible. The decision of AT&T to not support my phone is not technical.

[+] It has 2 SIM card slots, something that seems to be impossible to get in the US. I think only one of the 2 slots fully supports LTE.

>[+] It has 2 SIM card slots, something that seems to be impossible to get in the US.

The 6T and 8T has 2 SIM slots in their retail unlocked versions. T-Mobile 6T and 8T versions can be flashed to this config (but you will need to buy a new sim tray to hold both cards).

It's also pretty common now to see phones that have esim and a single sim slot in the US.

> I think only one of the 2 slots fully supports LTE.

Both of the slots support LTE; OnePlus has made some frustrating power saving decisions though, which force the secondary (non-active) SIM to 3G when it's not in use.

This can be disabled (at least on my 7 Pro running Android 10) via logkit following these steps[0]. Once disabled, the phone will fully support VoLTE on both SIMs.

[0] https://forums.oneplus.com/threads/dual-4g-networks-setting....

> It is not just "old" or 3G-only phones, it is any phone that is not explicitly on their whitelist.

This is correct. The whitelist that they're using specifically is here[0].

Some phone representatives will claim to people that they need a "5G Phone" - this is misleading, either on purpose (because the rep wants to increase their sales figures), or accidentally (because the rep isn't well trained on how to handle this situation).

AT&T will provide alternative phones for free, but they usually aren't great. Last I heard it was an iPhone SE (2020) for existing iPhone users and a low-to-mid range Android phone for existing Android users.

[0] https://www.att.com/idpassets/images/support/pdf/Devices-Wor...

> Beginning March 1, 2022, we sent cancellation notices informing session-based customers (AT&T PREPAID) that their account will be canceled on or after April 19, 2022, if they have not taken steps to upgrade to a compatible device.

> What type of device are you using? Customers using 3G and non-VoLTE devices are subject to immediate disconnect as we sunset the 3G network

This sounds like the competitor to the records for lunacy in history: one owned device¹ will not support their service - and they will cease the contract?! [Edit: they have closed the accounts...]

[Edit: sorry, but I believe I must reformulate the above before skimmers drill in their mind a wrong piece of information I slipped in out of confusion. Please see the further exchanges below with corrections and clarifications.]

(¹And how are they entitled to know what it is - it is not a trivial right to peek.)

3G is not only an internet service, it is also a voice service. Given that at&t closed down their 2G network, closing down their 3G network as well would mean that those phones would be unusable even for telephony purposes.
Right, it's been a few years since I re-read the Tanenbaum, and I got confused over the technical capabilities.

But the core issue remains: they have disabled the SIMs, they have reappropriated the numbers of paying customers.

From one of their employees: «While at the store they can reactivate your account with your old number if it is still available»

When one buys petrol, how can it the seller's business which engines will see it.

In the basicmost terms: if the connection technologies of some devices stop being supported by the infrastructure, what is expected is that the subscriber will deal with it in their own terms - not that the contract is ceased!

Yes, I agree that disabling the SIM cards makes little sense. I wonder why they did that. Perhaps they think that if customers haven't upgraded their phones yet it's because they don't intend to.
> From one of their employees: «While at the store they can reactivate your account with your old number if it is still available»

What the fuck? Here in Germany, customers have the freedom of porting their number over to a new provider 30 days after contract cancellation [1], precisely to prevent such scenarios.

[1] https://dejure.org/gesetze/TKG/59.html

Most prepaid plans have an account per device. You may log in with a single username, but then you have an account for each device you pay for.
A friend of mine uses AT&T and they shut off service to the SIM saying it was due to AT&T no longer offering 3G. My friend pointed out that the phone hadn't used anything but 4G, or LTE, in the last few years, and the phone didn't require 3G. AT&T suggested it was due to the move to 5G, and the phone wasn't 5G compatible. My friend pointed out that AT&T doesn't offer 5G coverage in the area. AT&T claimed the phone would not work. That was not the case. My friend explained that the phone would work with every band offered by AT&T in the area, and asked the rep to say so if it was simply a matter of AT&T prohibiting the phone. AT&T then returned service to the phone.

Unfortunately, the rep insisted that all telcos would follow suit, and there would be no phones used without 5G compatibility soon.

That still offers very little explanation about what their motives could be. Do they just want to generate some money, or are there actual concerns about backwards compatibility?
There are only three things that matter: Location, Location, Location.

The higher your resolution is the more you can be sold for.

Personally, I believe that they're worried about a repeat of this incident[0] - and the way they're ensuring that that can't happen is to test and 'certify' all phones before customers are allowed to use them.

Conveniently, they get to charge manufacturers for this certification process; and if consumers don't have a compatible phone, they get to advertise new expensive ones which come with installment plans.

Overall, it's a win-win for AT&T, and a loss for customers.

[0] https://www.theverge.com/2018/6/28/17515464/att-911-emergenc...

> there would be no phones used without 5G compatibility soon

With low level of obstruction, the distance range of 5G is half a kilometer. The distance range of 4G is ~30km. 5G covers roughly one fiftieth of the distance of 4G.

If they phased out 4G, people still owning a mobile telephony device would stop receiving service when out of urban areas?

No, 5G have lots of range. Its no worse than 4G, it just depends on the frequencies that the carrier have rolled it out on.

If its rolled out on 26ghz its bad in range. Sub 6 GHZ 5G rollout is as good or better than 4G on the same frequencies.

My carrier have rolled out 5G on 700 MHZ and I am seeing better coverage than their 4G network.

> If its rolled out on 26ghz its bad in range. Sub 6 GHZ 5G rollout is as good or better than 4G on the same frequencies.

Range will be the same, but coverage can technically be a bit lower. This is because the modulation used for 5G uplink (phone to cell site) - OFDMA - is more complex than the modulation used for LTE uplink (SC-FDMA).

This is the same reason you might’ve been in a very rural area and seen 2G. It doesn’t necessarily mean there’s a 2G-only cell tower nearby; just that the 2G signals are more resilient to interference and signal loss.

The downside to that resilience is, of course, much lower complexity, and thus it can carry less binary data.

Is it not just because 2g have traditionally been rolled out on lower bands?
What you're talking about is 5G mmWave. Previous longer frequencies remain usable with 5G. Last I looked into it mmWave was a tiny portion of 5G deployments, as it only makes in very dense urban areas due to the reasons you noted. Of course those mmWave stations presumably still support the longer frequencies because why wouldn't you if the goal is to fit tons of clients onto one station.
>With low level of obstruction, the distance range of 5G is half a kilometer.

Um, no. I regularly connect to a N41 sector broadcasting over 12km away and pull 300-400mbit off it. That's midband 5G, which most consider medium distance.

AT&T is running 3G on 850mhz which they can put a 5G N5 carrier on. This can do that kind of range with obstructions, but is less spectrum so will congest easier like T-Mobile's 600mhz N71 carrier.

EDIT: WCDMA (3G) was always the weakest for coverage. Geographic cell sizes actually shrink as more users connect https://en.m.wikipedia.org/wiki/Cell_breathing_(telephony)

Some of the earliest LTE devices did data over LTE and voice over 3G. Notably this applies to the iPhone 5s does not support voice over LTE - which you commonly see on Android devices as VoLTE. There’s a variety of other devices in the the same situation. The user experience on these devices often does not make it clear that audio is going over 3G.

This has caused many people to get notified of incompatible devices that they thought would work. The devices do continue to work, for now, but as 3G is shut down in a staggered fashion, they’ll seem like they work until the owner tries to make a phone call or realizes they haven’t received a call in a while.

IIRC - It's less voice over 3G and more voice over 2G but done on whatever radio interface you have. A question of using pre-IMS voice call interface vs. using IMS one (which was actually introduced with 3G, but first use for plain voice that most people have seen was WiFi Calling)
AT&T shut down their GSM 2G network in 2017 - the remaining circuit switched calls were going out over UMTS (3G) until the shutdown.
The radio interface used is 3G/4G, but it still used circuit switching instead of IMS (which uses GPRS channel - just like your 3G/4G/5G data - and SIP, iirc)
> Unfortunately, the rep insisted that all telcos would follow suit, and there would be no phones used without 5G compatibility soon.

This has approximately zero chance of being true. For instance, all iPhones before iPhone 12 lacked 5G. There's no way AT&T or any major carrier will get away with nuking support for iPhone 11, XS, X, 9, or 8. Probably not even iPhone 7, which still supports the latest version of iOS.

The rep said that 6G was coming soon, and my friend asked if the 5G phones would all be made as worthless as the 4G LTE phones are now. This was one of the reasons given for not wanting to purchase a new phone when their phone still worked with every band AT&T used in the area (which was proven correct when they reactivated the SIM).
Well a famous blogger, was it Randall Munroe? Recorded an extensive conversation with Verizon about their lying about their rates by a factor of 100.

So that works. Verizon's PR had to do damage control on that. That got around. That's how you get them.

Next time record the convo. Record all your convos. They love to tell you black is white over the phone, but then in court, turns out now I am not a lawyer or nothing, but I'm pretty sure they tell them black is black and white is white. American courts work pretty well, especially when it's that clear cut, as far as I see it.

There should be a call app, of course the same people you're talking about are against this it's the telecoms and the smartphone people in bed together (like AT&T and Apple with the original iPhone, openly, and this 5G business) but anyway, the following could still be done. It starts recording the minute "this call might be recorded" sounds. A tiny ML model trained just for that, not connected to the internet, that switches on record when it hears that.

How are you supposed to record calls on iPhones?

Wow the telcos in the US are f'ed, who cares what device you use on your account and when it eventually stops working because there's no 2G or 3G you fix that by getting a new phone with 4G or 5G.

Disabling phones because they're not "approved" is stupid but hey, US telco and stupidity are synonyms

Yeah it is insane that this is a thing. Nothing comparable happens in Australia for either phone service or ISPs.
In Europe some providers dismissed their 3G infrastructure and simply let their user know several months in advance, with several SMS communications.

«... Please make sure you will have a 4G and VoLTE telephone available for the end of the works, set for this date»

Looks pretty linear... It should be "base behaviour", what one should normally be entitled to expect.

I have multiple friends who have left AT&T because of this. It seems to me they are shooting themselves in the foot.
Rejoice, that at least you still get a basic-level-decent market! But that they arrived to that point suggests the contrary: overaccepting customers.
AT&T made it apparent that acquiring/retaining customers by being a decent service wasn't a priority. Instead they acquired companies to bundle like Directv and got on the government Firstnet corporate welfare scheme.
I thought all GSM telcos are required to work with any device you put the SIM card into? At least that was the case in the LTE days. Has the law changed? With the FCC getting so politicized I wouldn’t be surprised, but it’s still news to me that any carrier is allowed to have a whitelist.
Pretty sure the only service all carriers are required to provide regardless of whether a SIM card is installed is 911 service.
That's a different topic entirety.
GSM is a 2G technology. Most carriers have either already discontinued it or are going to in the near future.
Welcome, but: could you please e.g. avoid all-caps? Kindly check the guidelines, https://news.ycombinator.com/newsguidelines.html

Of course, we are sorry and concerned about this whole situation.

Edit: the original post disappeared: it mentioned that this user had service cancelled and telephone number reappropriated over an LG V30 - a 2017 device - because it was "not accepted in their system". It "joins the club" of many hit by the whitelist.

I'm on an MVNO that uses AT&T service, Redpocket. I had a phone (LG G8) that WAS on the whitelist and AT&T dissabled it after the 3G shutdown. I was without service for over a month until I gave up and bought a newer phone. Customer service had no clue what to do.
Google forces to use 2FA with SMS authentication, then AT&T disables phone number. Great.
The US has phone-number portability.

You may be disadvantaged but that number can be transferred to a new phone.

Or, possibly, your existing phone at a new carrier.

https://www.fcc.gov/consumers/guides/porting-keeping-your-ph...

You can't transfer a number you no longer have an account for.
Hrm...

File a complaint with your state AG's consumer protection office.

Most have a specific form (usually online) for telecoms issues.

How many crosswalks have you been hit in?
I thought this was the case too but after falling victim to these tactics myself, AT&T began to actively hold my numbers hostage. In my experience AT&T requires you set up a "TRANSFER PIN" that you give to the other carrier when porting, but in my case have repeatedly rejected the request with the correct PIN.

AT&T is a incredibly consumer-hostile company that does not play by the rules, can and will hold your phone numbers hostage, and as shown here will arbitrarily disable devices when it is convenient for them.

They're all but certainly in violation of law here.
Wait a second, sorry if I am ignorant on the matter but... carriers _whitelist_ phones in America? That sounds absolutely insane to me (as a European). Is there a particular reason why they do that? and also, is there any reason why it is allowed? I don't think I've ever heard of anything like this over here in my country. And even though I'm not a law person, I'm pretty sure something like that would either be illegal or just disaster for the company.
I think it’s a leftover from the old way where phones were carrier specific. While we had SIM cards, they had some kind of built-in chip that was specific to their carrier.
It's a combination of a technical requirement, and only officially supporting that required feature in certain firmwares. I have a phone model that is slightly different from the one on the approved list but it works OK. Not everyone got so lucky.

My Galaxy Note 8 supports VoLTE, but AT&T won't provision it and I don't really know why. My guess was that it would take extra work and they doesn't feel like doing it.

It's a combination of money
The phone likely uses 3g to do voice calls and AT&T ended their support for 3G earlier this year.
All major US networks are doing this, not just AT&T.

The spectrum is needed for 5G.

From the FCC:

https://www.fcc.gov/consumers/guides/plan-ahead-phase-out-3g...

t-mobile is not. The issue with at&t is they have a specifice whitelist of phones, and are using the 5g cutover as an excuse to force phones not on their very limitted list off their network. These phones work just fine with 4g, which is still supported.
Devils advocate:

So how many years should a company continue to support old technologies?

3G was first released in 2002 (20 years ago) [0]

4G was 2010 (12 years ago), which was the successor to 3G (though I realized "4G" is a debated term) [1]

To put this into perceptive, Samsung/Google don't even support their cellphones older than about 2 years old.

Now I'm not suggesting a shorter support cycle, but 20 years seems more than fair.

[0] https://en.wikipedia.org/wiki/3G

[1] https://en.wikipedia.org/wiki/4G

I don't know what devil you are representing? The assertion is that you can buy a new 4G phone today and get booted off their network for using it because it is not on a list of phone models they sold.
It's not an entirely accurate statement.

I can also buy a brand "new" telegraph today from Amazon for $10. Should carriers still support something that was created 100 years ago?

You can buy a phone with the latest technology in it, designed and built to tomorrow's specification; and AT&T still won't support it, unless the manufacturer has paid them to certify it and put it on this list[0].

Very few people are advocating that they keep 3G around using 5x5MHz of spectrum for little gain; people are just advocating that they not limit consumers from using the supported device of their choice regardless of whether it's on the list.

[0] https://www.att.com/idpassets/images/support/pdf/Devices-Wor...

>Should carriers still support something that was created 100 years ago?

No one is saying ATT should continue operating their 3G network. On what grounds are they terminating subscriptions?

Also, there's more than just Apple/Samsung/Google. Operators are shutting off 3G, but keeping 2G alive for a while longer for crap that's abundant, and doesn't need anything more anyway.

Leaving a small sliver of 2G service would have avoided obsoleting a lot of devices. Support emergency calls, very low data rate applications, and play an announcement if someone tries to make a call "we're sorry, your phone sucks, or we're too lazy to let it provision a VoLTE profile, so buy something new if you want to talk"
My home alarm company made all kinds of complaints because they had to upgrade the modem in my home alarm notification service to be 4G.
Distinguish shutting down 3G from terminating people's phone numbers who use non-whitelisted phones.
I had a phone that supported voice over LTE (volte) and wifi calling. Worked fine on another network, but that network did not have the coverage I need, so I had to go with AT&T. With their '5g' 'upgrade', they stopped allowing voice calls, as those would go over 3g. Except, there was a period of time where volte worked fine on at&t - my guess is when they were reconfiguring for 5g, they accidently configured things to work the way they should, but then realized their 'mistake'. I had to get a new phone since I need the AT&T coverage.
AT&T gave me a free iPhone SE because of this. I prefer Android using generic brands bought online that have a good feature set at a lower cost. None of these phones will work with AT&T even though they meet the technical requirements of the new network standard because AT&T is whitelisting select brands. This should be illegal.
I have an "old phone" not on their whitelist that supports LTE. AT&T sent me an "equivalent" (as in the lowest spec android phone they could possibly find) replacement phone and my old phone stopped working. I registered my sim card as using this new phone, then promptly put the sim into my old phone and my old phone works perfectly even though I am registered with the new phone.
AT&T gave me ample warnings the last year that this was going to happen to my Xiaomi phone. So now I have to carry my Xiaomi Max 2 (because I prefer using it when there's WiFi), as well as an old Alcatel Axel phone they gave me (just barely usable).
Some of the old cars use 3G for communication and those are going out of service because of 3G network sunsetting. My car got an software upgrade to switch from 3G to LTE. There will be problems for all kinds of devices relying on the 3G network.
January 2014, after only 3.5 years of being an AT&T customer, I realized in the previous year I had neither called anyone nor received a call. I still had an iPhone 4, and I only used the data. I cancelled my service. I went entirely without any phone of my own until March 2020 when I started using Google Voice with a wifi device and cable internet. Since 2014, I've saved at least $1000 on the stupid phone.