After my original post, it was brought to my attention that Katalon can support Xcode 10 now if we use Appium 1.8.2-beta. So, you don’t need to maintain 2 versions of Xcode any more - you can get rid of the Xcode 9.4 version if it’s less confusing that way.
If you have Xcode 10 installed in your /Applications/Xcode location, you can select it on the command line with:
sudo xcode-select -s /Applications/Xcode.app/Contents/Developer
You can install appium 1.8.2-beta with:
npm install -g appium@1.8.2-beta
If you’re still having issues, please check out this forum post with several troubleshooting steps:
If none of those options work, please let me know.
– Chris