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Get the download on smartphone compatibility and the freedom to bolus

We’re so thrilled that more than two million boluses have been delivered* via the updated t:connect mobile app!

But we also know that many in the Tandem Family have been patiently waiting for their opportunity. The No. 1 question that comes up is: “When will my phone be compatible?”

It’s a fair question. So we went to Geoff Kruse, our Vice President of Software Engineering, to get the update on compatibility.

Tandem Diabetes Care: Thanks for the time, Geoff. The top question we see from the Tandem Family has to do with phone compatibility. Why are some phones compatible, but some aren’t?

Geoff Kruse: The overall answer is that each device is individually tested to ensure that it functions safely and correctly. This is a first-of-its-kind device to be FDA-cleared on both iOS and Android where you are bringing your own consumer phone into a medical application where you’re dosing insulin.

We’ve worked with the FDA to define how we test consumer-grade devices to help each function safely with the pump.

Tandem: With that in mind, is that the reason why other features of the t:connect mobile app are compatible on certain phones, even if the feature to bolus from the smartphone isn’t compatible yet?

GK: Exactly. The secondary display, for example, is what the FDA considers a lower-risk feature. You’re not directly dosing insulin from it. You still have a human in the loop making decisions about whether what they’re seeing is matching their symptoms when they’re dosing insulin. With the smartphone bolus feature, the phone app is directly sending a command to the pump that will result in a dose of insulin.

And so, we need to make sure everything we do ensures that the correct dose of insulin gets sent to the pump. For example, with some phone models, a small screen could cut off part of the display. Imagine trying to input 10 units, but the screen only shows a ‘1.’

That’s a big difference, and a good example of a phone model that wouldn't pass a compatibility test.

Tandem: That’s really informative. But why does it take so much time to add additional compatible devices?

GK: Part of it is the individual testing and part of it is tied to the release cycles. Every time we do a new release, we have to do the compatibility testing, or some portion of it again, to verify that the current app version is compatible.

We have a testing process we are required to follow. After we go through that testing process we’re able to add new phones.

Tandem: So, understanding the rigorous testing process, how often are we adding compatible devices?

GK: As quickly as we can. I promise (laughs). Part of the initial launch is making sure that everything’s going smoothly with the devices we already support.

When we got approved, there were two compatible devices. We launched with 27, covering approximately 75% of our userbase. So we’re already on a pretty fast trajectory. As quickly as we’re able to test and show the devices work correctly, we’re adding them.

Tandem: We’ve been hearing about major operating system updates lately — iOS 16 for Apple and Android 13 from Google. Why are we advising t:connect mobile app users to turn off automatic operating system updates? Why is this necessary?

GK: Apple and Google designate their major releases with a number. For a major release, it’s that first number that you see, like iOS 16 or Android 13.

The reason that they do that is because when they make changes to the operating systems that are significant enough for them to bump that first number, they sometimes are making changes that could impact functionality or the application programming interface (API).

An API, for example, is Bluetooth. A major operating system update could impact, and this is just an example, how Bluetooth works. So time is needed to verify that Bluetooth still works. The t:connect mobile app is the same. We need to make sure that with a major OS update, our product is still safe and it works the way it’s supposed to.

We can do some testing ahead of time. But there’s a lot we still don’t know until the actual operating system is released.

A good example is Apple’s recent announcement. They announced a new phone, a new watch, and even though we have access to some operating system changes ahead of time, the final release still had dozens of changes that we need to account for.

We have to do the testing and make sure those changes aren’t going to cause a problem.

Tandem: Being on the engineering side, you probably don’t always see the end result of you and your team’s amazing work. What did it mean to you hear that the first bolus was delivered from a smartphone? And what did it mean to hear two million boluses had been delivered?

GK:I’ve been working on various versions of phone control delivery for roughly more than a decade. It takes a long time to develop a product that is going to be robust. It wasn’t just technical implementation. It was also bringing FDA along with us getting all the pieces in place.

We had to prove that it was still safe. What if somebody gets a call or text in the middle of a bolus? We had to work through every scenario.

It was so exciting to see that first one. And then to hear two million, that’s a really hard number to wrap your mind around. It’s amazing.

Thanks, Geoff, to you and your team for all you do to make a positively different impact on the lives of people with diabetes.

*Bolus delivery from the t:connect mobile app requires a compatible smartphone model and operating system, an app update, a remote software update on the customer’s t:slim X2 insulin pump and additional training. Only available to customers who reside in the United States.

t:connect mobile app: The feature set available within the t:connect mobile app is dependent on the pump software version and the compatible smartphone’s model and operating system (OS).

  • The Display and Data Upload feature set provides a secondary display of pump and continuous glucose monitoring (CGM) information, including display of your pump alerts and alarms, and enables wireless uploading of pump and CGM data to the Tandem cloud through an internet or wireless data connection. Standard carrier data rates may apply.
  • The Bolus Delivery plus Display and Data Upload feature set additionally allows users to request, stop, and cancel a bolus on the pump from the t:connect mobile app. At least one smartphone security setting must be enabled to utilize the Bolus Delivery feature of the t:connect mobile app.
  • WARNING: Always rely on your pump to make therapy decisions when using a smartphone that is incompatible with the Bolus Delivery feature.
  • PRECAUTIONS: Always rely on your pump to make therapy decisions if using a smartphone that is incompatible, the smartphone is lost or damaged, or the smartphone loses Bluetooth® connectivity with your pump. Important pump alerts and alarms are only received as app notifications when enabled and the app is either active or running in the background.
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