For 10.13.6, Xcode 10.1 is the last supported version Mac Os High Sierra 10.13 6 Installer Download OnyX is a multifunction utility that you can use to verify the startup disk and the structure of its system files, to run miscellaneous maintenance and cleaning tasks, to configure parameters in the Finder, Dock, Safari, and some of Apples applications, to delete caches, to remove certain problematic folders and files, to rebuild various databases.For 10.13.2, Xcode 9.4.1 is the last supported version.When the Xcode 7.0 - 10.x section of the Wikipedia page is checked, it can be seen that the quote above is not (entirely) correct, depending upon which version of High Sierra you have installed: However, once 9.4.1 is installed upon 10.13.6, then there is an update offered for the CLT on the AppStore to version 10.1, Looks like for 10.13.6 you'll need Xcode 9.4.1
has a good summary of compatibility versions. As it doesn't appear to have been mentioned in the existing answers/comments, for completeness, the last version of Xcode to run on High Sierra (macOS 10.13.2) is version 9.4.1, but on macOS 10.13.6 the last supported version of Xcode is version 10.1įrom Xcode want install on high Sierra 10.13.6:
