A few weeks ago, when opening the Dexcom app I started receiving a message saying I was required to update the iOS on my phone to continue using the Dexcom app.
No choice in the matter, if I don’t update by Jan 6th I won’t be able to use the Dexcom app!
So for context, let me re-phrase the two messages I got from Dexcom when opening the app, and put them together into a single paragraph…
You need to update your phone by January 6th to an iOS that we have not finished testing. Your Dexcom app won’t work on your current iOS after January 6th! So you need to update! But sadly, since we have not tested the new iOS to which we are requiring you to update, we don’t really know for sure if it will work correctly after January 6th either. Thanks for your patience in this matter, and please don’t rely on the phone app. Just use your cool 1980’s style receiver.
Sincerely, Dexcom, your friendly $27 billion dollar company, who can’t afford to pay for testing the phone app before you are required to upgrade to it!*
-No more fingersticks! (But as stated above, please don’t rely on the G6 app for monitoring or treatment decisions.)
Yeah. Confusing. Dexcom should tell you which operating system version to install; “updating” on both iOS and Android gets the latest, greatest, untested version.
It’s always worth repeating, here’s the Dexcom compatibility page (English version) for devices:
But the OS installed on the device also matters. These pages are more useful:
Both list the iOS and Android versions (which, apparently, are independent of the 'phone itself) and both say:
Highest supported OS:
iOS 26.1
Android 15
Minimum required OS:
iOS 18.6.0
Android 13
Followed by the all important:
You can use this app on any OS that meets the minimum requirements, but Dexcom recommends not updating to a new OS before it’s listed here.
So “or above” on the first page was a bug; that’s not what they say and it is a lie. The actual range is limited to iOS 26.1 (Google is more clear because it includes all Android 15 versions)
iOS 26.2 (so not supported) was released on December 12, 2025; it is essential to not install that (yet!)
I would avoid “upgrading” to anything beyond iOS 25 if I owned an iPhone. In nerd terms 26.1 and 26.2 are “minor” releases of “26” but, unfortunately, even minor releases break things.
It’s difficult to do this but it is possible. Periodically poll the compatibility pages while, at the same time, refusing to “upgrade”. When the “upgrade” is, in fact, supported, go for it. Be very very careful with the semantics of Dewey decimal numbers and the order in nerd speak; a requirement for “26” is met by “26.1” but a requirement for “26.1” is not met by “26” or “26.2” but is met by “26.0” and “26.1”.
The problem is that it’s not easy to pick the iOS version on the iPhone. When doing it with the upgrade option, you either upgrade to the latest or you do nothing.
Yes, there are some hackish ways around this, but it is not easy.
So in my situation, my choices for Dexcom were “won’t work at all” or “might not work”.
@Liam-M isn’t getting those messages, strangely and his iOS version is 18.4. He said he hasn’t seen any and he’ll keep an eye out over the next couple of days. If Dexcom stops working, Loop stops working.
Today is the 6th and he is having no issues atm ::knocks on wood:: Hopefully hell doesn’t break out after midnight.
Avoid the iOS update if you can. They did a lot of dumb stuff.
Like all of my clock alarm sounds got changed to some dainty sounding alarm that would not wake me up. They just decided - Hey, while we are doing this iOS upgrade, let’s go ahead and change the default settings you previously had for your clock alarm. And let’s not tell you. You can find out the hard way when you don’t wake up!
Who in the world would think after doing an iOS update - I better check my clock alarm sounds in case they got changed…
Sorry, I am aggravated at both Dexcom and Apple right now. But I still loves my FUD!
@ClaudnDaye While the manufacturers word is somewhat final regarding their support and willingness to replace prodcuts, like @Eric I’ve been confounded by Dexcom and Insulet’s “requirements” being out of date. Their testing seems to have “improved” over the last several months, but still leaves a lot to be desired. You/Liam and others using Loop or other DIY AID systems (if not already checking the respective sites once in a while) may want to check them before updating. For Loop, the LnL website ( Version Updates | Loop and Learn ) seems to be the authority for those more cautious; for those more adventurous, the Zulip Loop Chat forum (https://loop.zulipchat.com) provide even more recent info.
Of course nothing about a software update from Apple would change the way the measurements are taken, the packets are sent over bluetooth, or the iphone bluetooth receiver. Guess the worst thing apple could do is change power settings on the bluetooth antenna and you may miss some readings. Or maybe the alert settings are different and the dexcom alerts are now as dainty as your alarm clock.
I’d guess nothing has really changed but Dexcom hasn’t finished validating the configuration so May Not Work is more like CYA.
Yes; my work round was an attempt to work round that and it’s not easy, or rather it is easy but it requires checking every few weeks for that one, isolated, occasion when the “upgrade” is supported by Dexcom. If Apple revealed a couple of weeks before they cleared the shelves for the latest-greatest-least-testedest version of the OS, and maybe sent a notification to everyones’ 'phones then the problem would be solved. It’s easy but they don’t give.
Or if they, and their competitor Google, simply gave the option of upgrading to specific releases, not the most-brokenest one…
Or, shock, horror, if they just allowed us to choose.
No, it is really bad. The iPhone operating system (iOS) receives and processes the bluetooth advertisements from the G7 and it must send those to the relevant applications promptly so that the application can establish a connection to the G7 and engage in a secure communication to reveal the CGM data; our BG.
There are certainly more ways this can go wrong with an iOS change than there are dalmatians.
Hum. When I looked at the iPhone/Dexcom information Dexcom supports 26.1 of iOS and that was current until December 12 (IRC, I gave the exact date above).
Given that they are probably blacklisted from announcing support before Apple releases the iOS in question and taking into account my opinions of the very little amount of time that Apple or, to some extent, Google give their app writers to test, verify and prove their apps against pre-release versions of the operating system that are mostly broken I think 32 days to announce support is an unreasonable expectation unless said support was not tested.
In other words I’m saying exactly the opposite to everyone else. When Dexcom (or any other device critical to my continuation of life) fails to announce support for some third partying guys operating system I don’t much care so long as I still have a supported OS that works.
This isn’t WindowsXP; Dexcom want “18.6.0” and have not had time to test “26.2” and Apple do not afford us the ability to upgrade to, say “19”, or “20”, or “21”, or “22”, or “23”, or “24”, or “25”. Or even “26.1”. What gives? Something to hide?
I used Apple as a sacrificial example, Google are no better so far as I know (and I do use Google).
I hate Dexcom as much as everyone else, well, maybe more, maybe less, but this is not their fault; this is Apple’s.
Dexcom has been running fine on the iOS that was on my phone for a very long time. There is nothing that made Dexcom decide that it would not work after January 6th. Plenty of other apps on my phone would still work after that date.
The January 6th deadline was Dexcom’s choice, nobody else’s.
And if they did not have enough time to test the 26.2 iOS, then why did they force me to upgrade on that date? Why not wait until they have tested it before dropping their warning and putting out an update deadline?
All I know is I am getting this annoying message every time I open the ap. I don’t have a watch ( I keep thinking about it but haven’t yet). Do I really need to see this every time? It makes it about the 20th time today.
Thanks for your patience in this matter, and please don’t rely on the phone app. Just use your cool 1980’s style receiver.
