Apple regularly updates their iPhone software (iOS), computer software (macOS) and Xcode application. Loop's team of developers works hard to update Loop code as the new Apple updates are pushed out.
The most recent version of iOS is 12.1.4
The most recent version of macOS is 10.14.3
The most recent version of Xcode is 10.1
The most recent version of Loop is 1.9.4
The most recent version of watchOS is 5.1.3
The way Apple updates tend to happen is that one equipment's update will tend to require updating other pieces of Apple equipment. For example, if you update your iOS on the iPhone, you may need an updated version of Xcode to install a new Loop app onto your phone. And the new Xcode will require the volunteer developers of Loop to make updates to the Loop source code. Finally, new Xcode updates also frequently come with macOS updates on your computer.
Currently, if you have iOS 12 or newer on your iPhone, at a minimum you will need Xcode 10.1 and High Sierra macOS 10.13.6 to be able to build Loop 1.9.4. Older versions of macOS or Xcode are not compatible with the current Loop version on iOS 12.
Do not install beta releases of Xcode, iOS or macOS on devices running Loop.
If you are considering an update to your Loop app, check to make sure your computer and Xcode have any available updates installed prior to building the new app.
Computer access is only required when you are initially installing the Loop app, updating to a newer release, or making changes to the underlying Loop code. You do NOT need access to an Apple computer in order to troubleshoot or change Loop settings, such as basal profiles or carb ratios.
Where can you find your computer’s macOS version? Click on the Apple icon in the upper left corner of your Mac’s display. Select “About This Mac” from the dropdown menu, and it will display the macOS version number.
If your computer is running an out-of-date macOS, you can read whether you can upgrade to the latest macOS version here. The degree to which you can upgrade an older Apple computer will depend on the age and model of the computer.
Please note that for now, Xcode 10.1 will still install on computers using the last High Sierra update (macOS 10.13.6). This will inevitably change in the near future, as Mojave has replaced High Sierra for Apple's most recent macOS system. Therefore, Mojave (macOS 14) will eventually be a minimum requirement to build Loop app, likely with the next major Xcode update.