If you’ve lived in, done business in, have bank accounts in, or tax liabilities in several countries, chances are you need to maintain local phone numbers in at least a few of them.
While virtual numbers work for some use cases, often they are either unavailable or expensive for the countries I need, or don’t work with certain banks or governments.
So instead I have about seven or eight pre-paid SIM cards I need to keep active at any given time. I have a problem, I’ll admit.
Since moving to iPhone several years ago, I discovered that iOS has a built-in feature for forwarding SMS to other iPhones/iPads/Macs that you own. It really is a great feature, and works much better than the SMS forwarding apps I used on Android in years past.
So essentially I have the two most used phone numbers in my primary iPhone, and the rest of the are inserted in some spare iPhones I’ve stuck in a drawer with a hole drilled in the back for the charging cables.
The best iPhones for the job are the iPhone SEs from 2020 and 2022. At ~$/€100 second hand, the former is the cheapest one with dual SIM support: one SIM and one eSIM. At ~$/€200 second hand, the latter is the cheapest you can get that additionally supports two eSIMs at the same time. Unlike the iPhone 13 (US models) onwards it also supports the combination of SIM and one eSIM, making it the most flexible device for this purpose.
Anyway, apparently Apple quietly launched a new feature as part of iOS 18 that will get in the way of this approach:
In short, the point of the feature is to make it harder for thieves and hackers (and incidentally also police) to break into an iPhone. After a restart the device enters a more secure state, where important keys are still encrypted inside the Secure Enclave. This apparently includes the WiFi passwords.
In other words, if a device running iOS 18 hasn’t been unlocked in 72 hours, it will reboot and won’t connect to WiFi again until it has been unlocked the first time.
So going forward, the only way I can think of to use an iPhone to reliably forward SMS to my other Apple devices is to either:
- Not update it to iOS 18. This will probably work OK for some time, but I’ve experienced in the past that certain features (e.g. in Apple Home) will only work once all the Apple devices in your account is running the latest version of their respective OS. So this may not work long term.
- Get at least one SIM card an active cellular data connection in each iPhone. This may prove expensive since most if not all of the SIM cards are actually roaming. Intra-EU you may still find some plans or prepaid cards that will let you do this on a budget, so it is a possible workaround.
Since the first option is clearly preferable, at least in the medium term, I figured I’d post this PSA to warn anyone else that may be using secondary iPhones for the same purpose as me.