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Apple's Dual-SIM Tech Ruins Verizon Coverage (pcmag.com)
Apple's new dual-SIM function, which lets iPhone XS, XS Max, and XR owners use two cellular subscriptions at once, will come to new phones today. But the current implementation will have a huge negative impact on Verizon subscribers who choose to use dual-SIM in the US, PCMag reported Tuesday, citing engineers who have seen early builds of the software. From the report: Dual-SIM, a popular feature in the rest of the world, is largely unknown in the US. Generally, it's used for three things: roaming internationally, where you get a foreign SIM and also keep your local number; having home and work lines on one phone; or trying out multiple domestic services to see which one is better. Apple's dual-SIM relies on one physical SIM and an "electronic SIM" or eSIM, which is activated from a menu or an app. AT&T, T-Mobile, and Verizon promised eSIM support at launch, but neither Verizon nor T-Mobile will support the eSIM right now. T-Mobile is working on it and will support eSIM when its software is ready, the carrier told me.
[...] The problem comes when a physical Verizon SIM is pushed into the "secondary" position while the phone is in the US. Under the current software build, that kicks the Verizon connection down to 2G CDMA, an old network with significantly less coverage than the current LTE network. The old network also has no MMS support, and certainly wouldn't work for FaceTime. So Verizon customers may find they have perfectly good coverage with their SIM in "primary" position, but no signal and fewer features with the SIM in "secondary." When I asked Verizon about the CDMA network, the company said that 30 percent of its cell sites were now LTE-only, so there would be a definite coverage hit.
[...] The problem comes when a physical Verizon SIM is pushed into the "secondary" position while the phone is in the US. Under the current software build, that kicks the Verizon connection down to 2G CDMA, an old network with significantly less coverage than the current LTE network. The old network also has no MMS support, and certainly wouldn't work for FaceTime. So Verizon customers may find they have perfectly good coverage with their SIM in "primary" position, but no signal and fewer features with the SIM in "secondary." When I asked Verizon about the CDMA network, the company said that 30 percent of its cell sites were now LTE-only, so there would be a definite coverage hit.
Even the summary says that the networks promised support, then didn't follow through. Why that's being posed as Apple's fault in the summary makes no sense, unless you take into account the click-bait appeal of slamming Apple.
Still a nope. The secondary position only switches to that band because of the US network. Reread the article and you'll note that pushing the SIM into secondary outside of the US works just fine. The thing to note is that when you push a SIM into the secondary position, the device will attempt to ask the cell service to allow only inbound calls, since all outbound calls are done via the primary. Apparently, US cell networks explode in a puff of "WAAAA??" when asked to do this, and just go lowest common denominator in the confusion.
In short, asking a US carrier to provide an "inbound only" line is witchcraft and the iPhone just deals with the mass pandemonium as best as can be expected.
Apple is rolling out unfinished technology.
Not unfinished on Apple's side though. Works fine in Europe.
All that is unfinished is the U.S. carrier side, where carriers are dragging feet. I think Apple has done the right thing, which is to release it as is and let carriers start to take support calls based on shoddy or incomplete network support for what is a standard feature is many other countries...
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