O2 UK Warn Customers with Incompatible Mobiles as 3G Switches Off
Mobile operator O2 (Virgin Media) recently started emailing customers with handsets that are “not fully compatible with the UK’s 4G or 5G network” in order to notify them of their imminent 3G switch-off and offer an upgrade. But it’s worth noting that these notices will sometimes still get sent to people with technically compatible phones too, often leading to confusion.
Just to recap. O2 started the process of switching off their older 3G mobile (mobile broadband) network in March 2025 (here and here), which is due to reach completion by the end of 2025. After that it will separately also take them several years to completely retire their even older 2G service (here) as it remains necessary for various devices (e.g. Energy Smart Meters), as well as a fallback in areas of poor 4G and 5G signals.
The 3G switch-off will free up radio spectrum so that it can be used to further improve the network coverage and mobile broadband performance of more modern 4G and 5G networks, as well as future 6G services. The change will also reduce the operators’ costs and power consumption.
Advertisement
Customers will have already received notifications about this earlier in the year and O2 is now ramping that up as the switch-off progresses, in phases, across the UK. The main focus of this effort continues to be on customers who the operator has identified as having an incompatible device. The latter typically reflects handsets that lack support for 4G and 5G or which may be missing key 4G features, such as 4G Calling (VoLTE) and Wi-Fi Calling.
Copy of O2’s Latest 3G Switch Off Email
Hello [Customer Name],
We recently got in touch to let you know we’ll be turning off our 3G services. This change has already started, and we’ll be continuing the switch off across the country throughout 2025.
What does this mean for me?
You currently have a device that’s not fully compatible with the UK’s 4G or 5G network. After the switch off, you may experience a drop in call quality and be unable to access mobile data, including the internet and messaging apps like WhatsApp.
To keep using the UK’s mobile network, you’ll need to upgrade to a phone with 4G Calling before the end of 2025. All the devices available from O2 have the technology you’ll need.
Please note: upgrading your tariff won’t be enough to keep you connected once the switch off happens. You need to upgrade to a compatible phone.
What are my options?
To help make upgrading to a 4G compatible phone that bit easier, we’re offering you £100 off. To redeem your offer, simply use code [REDACTED] by:
– Speaking to one of our helpful agents in your local O2 store, or by calling 202 for free from your O2 mobile or 0344 809 0202 from any other phone.
– Logging in to My O2 online or via the app to see all your upgrade options. All our phones are suitable and 4G or 5G enabled.
Or you can purchase a new phone from any other retailer that sells 4G Calling compatible phones. If you have any questions, please take a look at our FAQ page.
What happens next?
The 3G switch-off will be here before we know it, so it’s important to make sure you get ready for it in good time.
If you find it difficult to access any of our services due to a disability or personal situation, we can make adjustments to help you manage your account. You can find more information at our Access for all page.
Take care,
O2
However, some of those receiving the new notifications have been left confused, not least because they sometimes already own Smartphones or simplified Feature Phones that do in fact support both 4G and 4G Calling. The problem here is that there can be a lot of caveats in the implementation of 4G Calling, both by the device itself and the network operator, which can add complications (i.e. just because a device says it supports 4G and VoLTE may not always be enough for full “compatibility“).
Mobile operators can usually detect when a customer is using a VoLTE compatible device (they may look at the device’s IMEI or its hardware features), although as above, there can be complications and this isn’t an exact science. For example, sometimes the device may support 4G Calling, but the network operator might not have set up the correct profile for that device to ensure that it works correctly. Equally, the handset itself may have a problem that prevents it from using 4G Calling properly. The feature might have also been disabled, either by default or manually.
For example, quite a few people own the Nokia 110 4G feature phone, which does support 4G Calling. Despite this, O2 has been notifying owners of these devices with letters like the one above (some customers will have received several texts and emails by now). But this often occurs with users of O2’s PAYG (Pay As You Go) plans because O2 still states: “WiFi and 4G Calling isn’t available on Pay As You Go at the moment” (here and here). This is of course quite disjointed of O2 and is a known complaint.
Advertisement
Customers of O2 can check if their handset is compatible online, which incidentally also reports that the Nokia 110 4G “isn’t compatible with 4G calling“, despite the fact that it does seem to work on their Pay Monthly plans (based on feedback). We’ve used the Nokia 110 4G as an example above, but conflicts like this also impact other devices that do technically support 4G Calling / VoLTE.
Mark is a professional technology writer, IT consultant and computer engineer from Dorset (England), he also founded ISPreview in 1999 and enjoys analysing the latest telecoms and broadband developments. Find me on X (Twitter), Mastodon, Facebook, BlueSky, Threads.net and Linkedin.
« GoFibre Expands Project Gigabit Broadband Rollout in Teesdale UK
Brsk Cuts Standard Price of 900Mbps UK Broadband to Just £35 »
Advertisement
Leave a Reply
Privacy Notice: Please note that news comments are anonymous, which means that we do NOT require you to enter any real personal details to post a message. By clicking to submit a post you agree to storing your entries for comment content, display name, IP and email in our database, for as long as the post remains live.
Only the submitted name and comment will be displayed in public, while the rest will be kept private (we will never share this outside of ISPreview, regardless of whether the data is real or fake). This comment system uses submitted IP, email and website address data to spot abuse and spammers. All data is transferred via an encrypted (https secure) session.
I was complaining about VoLTE incompatibility issues (and how it’s going to hurt us in the future) here a few times already. But I don’t think this is the main problem here. This message looks a bit scammy to me.
If they sent it to people with a 3G-only compatible phone, I don’t think they would be too concerned about this – more explanation would have been helpful. If someone is using an LTE, but not VoLTE compatible phone (or not VoLTE compatible on VMO2 only), I don’t think they care either. They were falling back from 4G to earlier standards for calls anyway.
Just as a test, I checked my phone (Fairphone 3) on VMO2’s VoLTE checker, and it says:
Sorry – your Fairphone 3 isn’t compatible with 4G calling. This means you won’t be able to use it on our network when we switch off 3G in your area, so you’ll need to upgrade to a compatible device soon.
This is simply a lie. The phone in question is VoLTE compatible (Vodafone supports it), and even after the 3G switch-off one could keep using it, just the calls would fall back to 2G, otherwise LTE data would keep working.
There’s no VoLTE standard, so phone brands need to work with the networks for VoLTE to work. A phone might have VoLTE on one network, but not on another. Sometimes it works with the MVO, but not some MVNOs. Since sometimes the process also requires a software update, phones that have reached end-of-life are screwed.
Then it depends a lot on how strict the networks are. Some are more strict than others and it might be a problem if you use a brand or device that isn’t very popular.
In any case, the best way to test this is to make a call while connected to 4G. If it drops to 3G or 2G, then forget it. There’s no VoLTE.
EE and Vodafone should turn off their 2G for regular customers later than O2, so I’d probably switch to them (or their MVNOs) when time comes.
It would be nice for pay as you go to be let onto 5G and 4G calling as standard. It’s not a new thing 5G has been around for a while now
The only operator who even has VoNR is EE ATM so doubt that’ll happen
@insertfloppydiskhere On top of that, there’s still no VoLTE on O2 for PAYG.
Nokia 110 4G is compatible with 4G calling for sure. I know it works on EE, Vodafone, Three and O2 Pay Monthly from my experience.
It comes up with a special icon and it it’s not working, usually toggling VoLTE off and on sorts it.
It’s not so much that we don’t have VOLTE compatible devices but that we are in something of a 4G dead spot at home to the extent that we only receive 3G most of the time. Our fear is that when 3G is switched off the signal will be non-existent. Of course we have WiFi but that’s not the point!
To be kind to them this message appears to have an emphasise 4G data. Most phones will drop to 2G for now and they acknowledge in the message that coverage may be effected for calling.
But I cannot believe that they do not have data on phone numbers that have connected to their 4G Network and used VoLTE/4G Calling, in say, the last 60 days. This could have been cross referenced to the email source file to exclude such customers.
Be nice if they had their 4G working properly, still it is better than Vodarubbish
The important thing, and the one we still haven’t been given any clear info about is the 2G switch off. Switching off 3G isn’t going to affect anyone unless they use DATA on an older device, but turning off 2G, or “restricting” it as O2 discusses (to smart meter use only), will cause chaos because that is when CALLS and TEXTS will fail for older devices. Still they haven’t said anything about dates for this. This is also where the matter of their mixed messaging about 4G calling (their name for volte) on non-contract SIMs comes to matter, whilst 2G is running anyone without a system set up for their 4G calling just drops back to 2G calls/texts. My understanding is that the lack of 4G calling applies to all SIMs bought as ordinary PAYG SIMs, even if you then set up a monthly bundle through the O2 website, correct me if I’m wrong but the mixed messages from O2 imply this is a matter about the SIM hardware not the chosen plan which affects 4G calling compatibility. Still the ony thing I can find about dates is the PiBlu technologies page, unofficial and some years old now but suggests O2 will stop inbound 2G romaing this October, then end 2G human use entirely in 2026. It would be very useful to actually have some officialy verified information on what is going on here. Thanks
I assume they want to see how the 3G shutdown goes before making a decision on the 2G restrictions.
I wouldn’t worry. They should give you some time to prepare and, if needed, it only takes a week or two to order a new EE or Vodafone SIM and transfer your number.
There was this from a while back with tentative dates:
https://piblu.co.uk/2024/08/28/switch-off-announcement-o2-2g-and-3g/
Key Dates
1 October 2024 – Stop-sell will commence on 2G and 3G IoT services, meaning these will no longer be available to buy.
1 October 2025 – Withdrawal of 2G and 3G services for inbound roaming users only (excluding Telefonica Spain), to save capacity and limit growth on 2G and 3G domestic services.
31 December 2025 – Location-based switch-off of 3G services will be phased in, starting in January 2025 and completing by December 2025. This will lead to a full withdrawal of O2’s 3G services by 2026. We will provide details of affected locations as the switch-off progresses.
1 October 2026 – 2G services will be restricted to existing IoT traffic and emergency calling outside of 4G coverage only.
It’s the same with 3G switch off as well as digital landlines. The entire society cannot be held back by a minority, albeit a large minority who aren’t prepared, don’t want to change etc. Whilst I appreciate some of these tend to be the more vulnerable in society, I think we have to drop the final curtain on these older technologies then pick up the pieces afterwards.
I do hope the networks are ensuring that all generations of mobile network connected security pendants work, either using 4G VoLTE or 2G fallback (with decent Sig strength)
Many of these make a hands-free voice call (built in speakerphone) when the pendant button is pushed. Often the SIM is a special all networks roaming SIM so it can use whichever network has best coverage
Change “networks” to “telecare companies and their equipment suppliers”. It’s the same argument that BT and Virgin face on fixed line, where no amount of prep work, industry announcements, access to test labs seems to be enough for the firms that don’t want to do anything at all and expect the telcos to bear the cost and the negative PR.
I think VoLTE works now on PAYG – I made two calls from 4G devices (one a full Android Motorola phone, one a Nokia 110) and they both had 4G showing. I’ve checked the call log on the device they were made to and they both come up as ‘HD’ calls in the history.