Our project plans to upgrade Xcode from 16.2 to Xcode 26. We’ve noticed that the information on https://developer.apple.com/support/xcode/ states that the Deployment Targets for Xcode 26 supports iOS 15–26.1.
However, the Deployment Targets for our current project is set to iOS 13. Does this mean that we must set the project’s Deployment Targets to iOS 15 or higher if we want to upgrade to Xcode 26? Can we still set the Deployment Targets to iOS 13? If we upgrade to Xcode 26 and set the Deployment Targets to iOS 13, will there be any problems?
Despite what the documentation states, you can actually manually enter a deployment target of iOS 12.0 or later in Xcode 26. If you try to set a deployment target older than iOS 12.0, you get a build message that it only supports iOS 12.0 and later.
So yes, you can support iOS 13.0 with Xcode 26. But you will not be able to test on anything older than iOS 15.0. There's no support for simulators before iOS 15.0. And I don't think Xcode 26 will let you connect devices with iOS older than 15.0.
The only way to test would be to have actual devices with iOS 13 and 14 and to install the app through Test Flight or Adhoc deployment.
But you have to ask yourself why you want to support such old versions. There have been so many API changes since iOS 13. Your code is going to get really complicated with lots of if #available checks. You should seriously consider updating your deployment target to iOS 15 or even iOS 17. Existing users of your app will still be able to use the current version of the app on their older devices. Anyone with newer devices will be able to update to your new version.