Xcode 26.4.1 was released yesterday. It updates the Swift toolchain from 6.3 to 6.3.1. Swift binaries are not backwards compatible by default, which means that some of our precompiled libraries need to be recompiled at every Swift compiler version change. Otherwise it fails with the error `unable to resolve Swift module dependency to a compatible module: XXX` when importing the library (keyword being “compatible” here).
Today, our CI no longer builds out of the blue because the stack `osx-xcode-26.4.x` now resolves to Xcode 26.4.1. Which is a breaking change for our project because of the Swift compiler version thing. Since we have no way to force Xcode 26.4.0 on Bitrise (there is no such stack), we are forced to perform an emergency update of the whole project to Xcode 26.4.1 if we want to keep using the CI.
My feature request is to be able to pin a specific minor Xcode version in the stack, because otherwise it allows unsupervised breaking changes, like the one that has happened today. Please let me use Xcode 26.4.0 if I want to.