BEWARE of buying iPhone 13

I just purchased a new iPhone 13 Mini. I was excited about it fitting nicely in my pocket and about linking it to my Apple Watch so I could continue to get my Dexcom G6 readings on my watch. The Apple Watch linked easily to my new phone, but the Dexcom App refused to open. When I clicked on it, it blinked for a moment and went back to my Home Screen. I checked to see that the Dexcom App was still on the phone and that everything was ready to transmit. All systems appeared to be ready, but I still could not get it to work. So I called Dexcom Tech and learned that DEXCOM WILL NOT WORK WITH THE IPHONE 13 yet, NOR WILL IT WORK WITH IOS 15.0.2. I asked the tech when they expected to upgrade the Dexcom software so it would work, and he said that he did not know. All he could do was to report “the problem” to his bosses and perhaps they could speed up the software compatibility process.

I am very disappointed 1) that the people at the Apple store did not warn me that Dexcom would not work with the iPhone 13 or with IOS 15.0.2 (especially since my salesman also was a T1 diabetic), and 2) that Dexcom cannot seem to keep up with technology updates.

So if you are thinking of upgrading to an iPhone 13 for the holidays, know that right now your Dexcom system will not work with the phone or with the operating system.

It’s a perennial problem. As long as I’ve had a Dexcom they’ve never been completely up to date to the most recent IOS. Thus far I’ve found that the app works anyway, though it throws up a warning when I launch it. I’m currently running 14.8 and it’s ok, but if it absolutely won’t run on 15 I’ll certainly hold off. There’s a security update pending, but it’s just to 14.8.1 so probably safe. I don’t like leaving security holes unpatched!

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Sorry you got burned by that @SherryAnn. Can you return the phone? I’m certain you will have saved a few people from repeating your mistake.

Since I use the DIY Loop system, I regularly check for compatibility between my iPhone model, my iOS software level, my Mac OS level (needed to build the Loop app), and my Xcode developer software level.

Orchestrating this software upgrade dance between all these interlocking pieces seems needlessly complex to me and I pay attention to those who follow these issues more closely and thoroughly than I am able.

Are you aware that Dexcom publishes a compatible list of iPhones on its website?


I am using iOS 15.1 on my iPhone XS with no problems. There are many other people on Facebook who report that Dexcom is working fine with their iPhone 13 and others who are reporting problems.

Have you deleted the app and installed it again from scratch? That seems to be a fix for some people.

Don’t give up trying to get it to work because most of us have success using the Dexcom app when technically it isn’t supported yet.


I’m running 15.1 on an SE iPhone. It runs the Dexcom app ok. It is other stuff that annoys me.

I’m running 15.0.2 on an iPhone 12. I’ll bet it will work but you might need to delete it completely and re-download.

The Dexcom page states that my phone OS is not compatible. Also, iPhone 13 isn’t even on the list.

But I expect it will work regardless.

This is from the page:

Dexcom Products compatible with iPhone 12 Pro


OS Range Set(s):

Dexcom G6 app iOS 14.1, 14.3 - 14.4.1

If your OS falls outside of this range(s), your device is not compatible.

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With the iPhone 13, I cannot even get the App to load, so I have no opportunity to get the security warning. I, too, have had the warning on other phones in the past but things worked fine. This time, I cannot even get the App on the screen, and Dexcom as much as told me that I should not try “for a while.” My husband called Apple, and they said that they give all of their venders a 4 month notice and the new codes so the venders will have time to update their software before the new Apple hardware comes to market. Dexcom made 22 BILLION dollars last year – too bad they could not afford to hire a few more software engineers to better serve their customers.

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Yes, I know about their compatible list on their Website. My bad for not checking it out, although the iPhone 13 tells me that it IS compatible… it just will not let the App load. Maybe that is wishful thinking on Apple’s part. I cannot return the phone and get my old one back because everything they sell is IOS 15, and they erased my old phone as I watched. The ship has sailed. I will just have to use my Dexcom receiver for now and wait until Dexcom gets around to supporting the iPhone 13. It’s just a shame that they never can keep up with others’ technologies.

Laddie is much more active in the FB community than I am. Have you tried her suggestion to delete the Dexcom app and then install it from scratch? At this point, there’s no downside to trying that.

Living with the receiver only until Dexcom figures this out isn’t a bad workaround either. Good luck!


Huh… that is strange. I’m sorry to hear that you are having this problem, but…. I have an iPhone 13 running iOS 15.1 and I am having no issues with the dexcom app…

I will try that today. Thanks for the help.

Dexcom tech support had me do that recently after I was having a lot of bluetooth dropout issues. Asked if I’d recently updated IOS, and I had, though still some flavor of 14, not 15. Delete & reinstall does seem to have fixed the problem.

UPDATE: I tried what Laddie suggested; I deleted the old Dexcom app and completely reloaded it on my phone. This time, it appeared! Then I started from scratch and did the same thing in pairing it to my old Apple Watch. At first it did not seem to take, but the second time backed out and logged back in, it worked!

So thank you to all who have helped me overcome this major roadblock in getting my watch to work with my iPhone 13 Mini. I still say that Dexcom is behind in keeping their Tech reps informed and in keeping up with software advances, but for now I am happy with the results.


@SherryAnn the words of @Laddie are true and can be trusted. Additionally, I test mission critical software for financial & healthcare.

These are the results of my testing on an iPhone 12 Pro Max with the iOS notediPhone app list. 22 October 2021

Most of use our phones as primary display devices or data relay devices.

If you use an Apple device, iOS 15 was released 20 September. On 5 October 2021, Apple released iOS 15.0.1 upgrade.
On 11 October 2021, Apple released iOS 15.0.2 called a security update.
On 1 November 2021, Apple release iOS 15.1 was installed.
I have installed the upgrade and tested it on an iPhone 12 Pro Max against:
*(1) t:Connect version 1.5
*(2) Dexcom G6 version 1.9.1
*(3) Dexcom Clarity 2.16.0
*(4) Sugarmate 2.6.23
(5) Tidepool v3.1.3
*(6) Dissend 1.12.

See About the security content of iOS 15.0.2 and iPadOS 15.0.2 - Apple Support

Additionally, I have updated my Series 3 watch to WatchOS 8 & use Dexcom G6 with no visible issues.

My testing checked the phone apps for normal app function. Here is a screen shot of my phone from tonight. Sad to say, you were give seriously bogus information.

Hope this helps.

@SherryAnn see reply.

Using iOS 15.1 on iPhone 12 Pro and watchOS 8.1 on Apple Watch series 4. No problems with G6 or Dexcom app.

Is sugarmate really working for you. Mine stopped on nov 4. I haven’t gotten readings since then
I didn’t see a new version on the ap store.


I still HATE the facial recognition on it. I returned the iphone 12 because of that and was hoping the 13 would have a fingerprint option available. It doesn’t. But I caved because I needed a bigger memory than on my iphone 8.

I used to just be able to reach over and hit it with my finger. But I have to pick it up now and our room is pitch black so forget it recognizing me, so I have to swish it and I have to enter my code. This wakes me up more when I just want to spot check my BG level like I’m used to.

So I could use help!!! I haven’t figured out how to keep it unlocked so it will just come on when I touch it? I can keep it on without it shutting off…that doesn’t work for me, too bright. But it would be nice at night to just touch it and it come on so I can see my BG number easily when I want.

Or is there an ap that keeps the BG number up on the screen, but maybe only the numbers are lighted so it’s not intrusive when sleeping?

It looks like my other option is using my reader only at night. I can do that but I would have to do a forced shut down of my phone every night, which I don’t really want to do. I hate both going off with an alert, you shut off one and then the other goes off 2 minutes later. And while I can go a long time without an alert at night, I can have enough clusters because of DP flaring up, not reducing enough of my basal after a snorkel day etc…that having 2 of them to cope with I just don’t do.

So I can make it not shut off and leave it open so I can look at it, but it’s too bright, even at it’s dimmest setting on the Dexcom ap (white). I could drape something over it and just pull it off, but that sounds like a disaster waiting to happen when I’m half asleep.

I am wondering about Nightscout…but I like the dexcom and the clarity ap and my Dr reads that. I seem to remember there was an issue one time about having both???

Anything else that is working for people?

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So facial recognition works for me at night. The light from the screen is enough for the camera. You could try to reset your face parameters. At least give it a shot.
I too would prefer a fingerprint reader, not least because my phone doesn’t recognize me when I’m wearing a mask, like while shopping!

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You could use an Apple Watch set up to activate the G6 app upon wrist-raise. It’s a relatively dark screen that will not sear your light sensitive night vision. It’s not a good suggestion if you don’t have or want an Apple Watch but I thought I’d mention it.

I don’t use the watch at night since that’s the time that I charge it. My solution is to use the Loop app which can run in dark mode. If Dexcom had a dark mode display, that would help for requests like yours.

I like Nightscout and it runs with a dark background. I think it would work for your requirements and it has some added benefits like keeping track of my infusion site age and Dexcom sensor age.

You could set up a Siri command that announces your BG, with data drawn from the Dexcom app. When I say, “Hey Siri, BG,” she answers, “OK, viewing, you’re 102 and steady.” It’s been a while since I set this up so I’d have to do a little discovery to see the step by step process to make it work. This function works at the Lock Screen.

Here are the instructions to set up a Siri Shortcut to announce your current BG.

It also displays a small Dexcom chart on your screen.

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