New iPhone or iPod

This section is for Loopers who want to transfer their Loop to a new device.

(Note: the device can be any compatible iPhone or iPod – for simplicity – we just say phone on this page)

The LoopDocs page (Updating) has detailed information on getting ready to build the latest version of Loop, which probably requires update of macOS, Xcode and perhaps accepting a new agreement for your Apple Developer Account as well as downloading a fresh copy of the code.

Breaking news – if you are on Loop-dev (soon to be Loop 3), you can build from GitHub (without a Mac computer and no updating steps required). This is new, so documentation is a work in progress. Here’s the LoopDocs Link to the GitHub Build Overview page. You must have an Apple Developer account and you might still need to accept a new agreement.

WARNING: If you need customizations, stick with the typical Mac and Xcode build for now.

You should always be prepared to start with a blank Loop app (save all your settings and be prepared to switch to a new pod before using the new phone). But most people find all their settings (and even the pod session / Medtronic pump info) transfer successfully using the steps on this page.


  • Plan to keep your old phone until the transfer is done.
  • You can continue Looping with the old phone (perhaps just on WiFi) until you are ready to transfer the Looping activity.
  • Even if you’re turning in the old phone for credit, ask to keep it for a week before turning it in.  Most places allow this.

WARNING: If you are using a different Apple Developer ID for this build, then your settings will not transfer and you will wind up with 2 Loop apps on your old phone. (You can switch to using the new app, and delete the old app on your old phone before setting up a new phone, or just start fresh on the new phone)

Prepare for the New Device

Update the Loop app on your old phone first using Loopdocs (Updating) (or the new GitHub method)

Why should I do this?

  • The first thing you do with the new phone is update it to the latest iOS so you can do the transfer all of your phone settings (using the standard Apple method)
  • This way you’ve worked out the kinks on a new build with that iOS using your old phone
  • Using the Mac and Xcode and download new code method?
    • Check out the minimum versions page on LoopDocs to determine the Xcode version required for new iOS and macOS version required to support that version of Xcode
    • Then move on to step 1 below
  • Using Loop-dev and the new GitHub Method – you can skip the Mac and Xcode update and downloading code steps – BUT – you will be building Loop-dev and you cannot add customizations
    • Make sure you have the GitHub method working and build onto your old phone
    • Then update the old phone to latest iOS and you are done
  1. Update your computer to the required macOS
  2. Update your Xcode to required version
  3. Update your old phone to the latest iOS
  4. Download the desired version of Loop
  5. Build Loop on your old phone – make sure that you only have one Loop app on phone when done
    • If there is more than one Loop app, then you probably built using a different Apple Developer’s ID
    • This means that you will have to set up the new Loop app, from scratch on the new phone – plan accordingly

What if the build fails on the old phone?

  • Xcode does not do anything to the existing app on your phone if the build fails
  • The old version of Loop keeps on running
  • You have time to figure out why the build failed and fix it

Set up New Device

Do the standard Apple transfer from old phone to new phone, but keep looping with old phone

Build Loop on the new phone using one of these methods:

  1. Mac and Xcode method:
    • Open Xcode – use the same build as you used for the old phone
    • Plug in the new phone to the computer (trust phone/computer) and hit build
    • Build Loop on the new phone
  2. GitHub and TestFlight method:

Transfer Succeeded

    Success: It worked and all your settings are there.

    IMPORTANT – check every setting – make sure all the basal, ISF, CR, Insulin Selection and ranges are correct before setting up the new phone for Looping use. 

    Dexcom App

    The Dexcom app might have transferred successfully, but it’s not a bad idea to install that fresh on a new phone. It may be required to do so with iOS 15.

    Be sure to record your Dexcom Transmitter ID before setting up the new phone for Looping use.

    You need to have your Dexcom Transmitter paired to the Dexcom app on the phone being used for Looping

    Loop Built but Transfer did not Succeed

    Go to LoopDocs (Setup) for information on how to add settings and CGM and pump.

    Complete Transition to New Device

    You have to turn things off on old phone because only one phone can connect to Dexcom or Rileylink at a time.

    Old Phone

    • Go to Loop on the old phone and slide the slider for Rileylink to off (if using DASH – skip this step)
      • DO NOT DELETE PUMP if on Pods – that cannot be reversed and you might need to switch back to old phone
    • Go into phone Settings -> Bluetooth and forget the Dexcom
    • Turn off bluetooth on old phone

    New Phone

    • Make sure the new phone has bluetooth turned on
    • Make sure Rileylink is near the new phone – it should connect automatically (not needed for DASH)
    • Delete the CGM in Loop (so you can connect Dexcom)
    • In Dexcom app, you can keep using your current sensor session
      • you might need to delete and reinstall the Dexcom app for it to work
      • pair the new transmitter (it’s not really new, enter number)
      • start a new sensor (it’s not really new, enter no code, ignore calibration warning)
      • within 5 to 10 minutes, Dexcom app should read the current session and keep going
    • In the Loop app, add CGM with the current transmitter serial number
    • Wait until you have a green loop (may take 15 minutes)
    • IMPORTANT:  your COB and IOB might not carry over to your new phone.
      • Loop reads from Apple HealthKit and might restore COB and IOB from health – this assumes health is stored on iCloud and synchronized between old and new phone
      • If your COB and IOB show up as blank, you can go open loop for 3 to 6 hours or add back your insulin via Apple Health to the time that the boluses and positive temp basals were recorded on your old phone: Apple Health/Insulin Delivery/Add Data.  Wait about 5 minutes for that insulin to show up in Loop as Active Insulin.  Finally, add the Carbohydrates to Loop by entering them in your Add Carb Entry screen by rolling back the Date/Time wheel to the time of the original entry(ies).

    Old Phone

    • In the Loop app, delete the pump (if using Medtronic) and CGM
    • Go into phone Settings -> Bluetooth and forget the pod – it will show up as TWI_BOARD or NXP_BLE

    You can either keep the Old Phone as a backup or reset it and turn it in for credit or give to some deserving individual.

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