Original article ISPreview UK:
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.
NOTE: The UK government and all major mobile operators are jointly aiming to phase-out existing 2G and 3G signals by 2033 (
here).
EE,
Vodafone and
Three UK have already switched-off the majority of their 3G platforms, with a few exceptions.
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.
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.
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.
