Voice on Nokia 225 no longer working.

I'm assuming that Kai OS devices still work since it's my understanding that the Nokia 2780 and 6300 are still functioning.  That may be a wrong assumption since I don't have any Kai OS devices.  As for what changed, I don't think it's anything in your handset that changed, but rather that Google made a change to their VoLTE specification that either intentionally or unintentionally blacklisted all handsets that don't have a specific something in their ROM which allows it to continue to use VoLTE.  What that specific something is, or what it does, I don't know.

But whatever this is, it would be good for T-mobile tech support to tackle this issue and let the customers known as there are a lot of handsets out there that are 4G/LTE/VoLTE capable - and were working using these protocols on the T-mobile network until just recently (long after the 3G shutdown).

Okay, if it's KaiOS, what changed? And how did my phone receive this change?

The past few days, the phone has been displaying this message: "Settings update available. Update?" (or something similar). When I choose to update, it says, "There was a problem with your memory card. Update failed" (or something similar). Hey, thanks.

Still plugging away on 2G for now. Works when there is a signal, which is in most places

I think the poster above who said that Google changed something in their VoLTE implementation may be correct.

The issue is being discussed here on Reddit and the person who started that thread and a commenter has identified two Android handsets that (a) lost VoLTE (on Android 7) and (b) didn’t have VoLTE or IMS registration on Android 9 but saw it begin to work when he upgraded to Android 11.

From that discussion "So my guess is the speculation is correct. Google has changed something that prevents older Android handsets and non Android/iOS/Kai handsets from using VoLTE."  It's probably more correct to say older Android versions, but what exactly changed?

Update: I drove to an event around 3 hours away yesterday, out in the country. When I arrived, I had no signal. But lo and behold! VoLTE had turned itself back on (I didn't switch anything). Excited, I waited until I got back in range, and made a call to my wife. VoLTE was still on. But the call didn't work anyway. I heard nothing. Later, she said it rang, but was just a dead line when she tried to answer.

After a couple of tries like this, I turned the phone off and on. When it came back on, VoLTE was gone.

This suggests that the 4G network signal is the thing bricking VoLTE on the 225. Once I lost the signal, perhaps the phone was able to go back to VoLTE without interference from the network.

Thanks to those who suggested switching to 2G. This works, though as people said, the signal can be spotty. In fact, I have gotten my Nokia 105 (3G and below only) to work again in the US (even though, supposedly, it does not use US frequencies - it's a European model). Since the 105 is pretty much identical to the 225, except smaller, it's a better choice.

Finally, switching to 2G fixes the problem of incoming texts having the wrong timestamp. So it seems that the weird text timestamps are a 4G issue as well.

I purchased the Nokia 225 4g as a cell phone for my elderly mother after her previous phone aged out of the 2g network.  The primary requirements were simplicity, reliability, and most of battery life.  The classic Nokia Feature Phone was a good replacement since if she forgot to plug it in for a week, it would still have battery life, unlike most all smartphones. Style, apps, and internet access are not required

The plan I have for it is a Pre-Paid Talk and Text only plan that is no longer offered.  Exactly what she needs and the cost to me is minimal since she only really uses it for emergencies.  The previous phone did still work, though very weakly and intermittently, on the 2g network at her home and I purchased the Nokia for the 4g ability when I found she couldn't call out from her doctor office for a pickup.  It worked excellently for months, but now the Nokia times-out of the 4g network when making voice calls and MIGHT connect to 2g, and then if is does, the signal is still flaky at best and often drops.

I'm thinking that T-mobile wanted/needed to make a VoLTE change that wouldn't affect (or perhaps would help) the majority of their userbase and didn't consider our tiny segment of users that would be cut off.  Or perhaps they did know it and were either willing to lose us for the greater good or were being evil and hoping it would force us to pay for one of THEIR phones ($) and/or move to an account with a data plan ($) and, hey, if we weren't willing to do that, then fine, leave, we weren't making much money off you anyway.

I would be very surprised if, for the above reasons, they put any real effort into fixing the problem affecting the Nokia 225 4g users.  The cost in time and people power would not outweigh the cost of losing a speck of users.  I wonder if this is an issue with other non-Nokia 225 users using the same plan setup.  I'm guessing that the two or so feature phones T-Mobile Prepaid does sell must still work on their network somehow.  It would be a smart move on T-Mobile's part to reach out and say, "Hey, Mr. Hazel Ra… You've been a uninterrupted T-Mobile customer of ours for the last 18 years… sorry for the inconvenience we've caused you through no fault of your own.  Here's the cheapest refurbished phone we sell that will continue to work on your plan, we'll ship it to you for free.  Thank you for being a loyal customer… tell your friends about us!"

That last part was to you, T-mobile, just in case you missed the subtlety.

Following up, switching to 2G or 3G does not work. Just says no network and doesn't function (even to find E or G).

Also, all other flip phones on the US market are either locked, crap, or both. Don't want to switch.

I am having the exact same problem. Nokia 225 worked with VoLTE for a month or so, then stopped. VoLTE was not using any data, so it doesn't have to do with data. The problem must be with the network itself. Wonder if anyone has this phone working with AT&T or Verizon?

Interestingly, I used to have Tello, where the Nokia worked on VoLTE. When that stopped, after a week or so of outage, I switched to T-Mobile itself. When I switched, VoLTE worked for maybe 4 more days. Then stopped. How could that be?

The phone will now occasionally make calls using the ancient E or G networks, but I seem to have no control on whether or how it accesses these older networks. Also, their coverage and quality is poor.

Texting works fine, except the timestamps on the incoming texts are wrong by an hour or two. However, this timestamp problem predates the VoLTE issue.

Has anyone solved this?

I called up T-Mobile about this issue (again), and they recommended that I contact Nokia about it. Nokia, in turn, recommended that I switch the network type to "2G." That turns out to work for me: I can make and receive voice calls as before now. However, it's a crutch: as Hazel Ra noted, the 2G signal is weaker than the 4G signal, so conversations are broken and calls get dropped. I asked Nokia about this via email:

I then called T-Mobile back to ask whether their 2G network will eventually be taken down, and whether they play to fix this issue with the 4G in some phones. Unfortunately, the rep spoke imperfect English and didn't understand all my concerns. She did note that the network in my area is currently being upgraded so the signal should be getting stronger, but I'm not sure that's the 2G signal she was referring to. When I griped that this has been going on for two months, she credited some money to my account. That's sort of taking responsibility, but it doesn't indicate whether anyone is working on a real fix. So I can't tell from this whether Nokia is taking real responsibility for this apparently-known issue, or whether T-Mobile is, or whether no one is.

T-Mobile's APN settings haven't changed in what seems like forever.  You can find the APN Settings though here. 

https://www.t-mobile.com/support/devices/not-sold-by-t-mobile/byod-t-mobile-data-and-apn-settings

I have the same exact problem as PineApples and Finlator to the letter.  Nokia 225 4g.  T-Mobile account is only Talk and Text… no data.  225 has VoLTE abilities and has been working fine for about a year without any data plan and no way to update itself with a newer software version.  Did a full reset / wipe with no change.  If you attempt to make a call now and wait, you can watch the LTE 4 bars dwindle from five bars to zero bars and the LTE will switch to E and it MIGHT connect with a single bar on E if there is an old tower nearby, but it is very rare and unstable if it does connect.  If I go into the settings and change the network type to "3G/2G", it doesn't go through the attempting to use LTE, but only throws up one bar and just as unstable and rare.  Something certainly seems like it changed on the T-Mobile end.  Any chance the default APN the phone/sim comes with has changed… could it be fixed with a corrected APN if VoLTE is the primary way the 4g voice works?  Just an idea.