ERROR ITMS-90725: "SDK Version Issue. How to rebuild from . App file

I am trying to submit my updated iOS app via application loader but I keep getting an SDK Version Issue. ERROR ITMS-90725: "SDK Version Issue. This app was built with the iOS 8.0 SDK. All iOS apps submitted to the App Store must be built with the iOS 11 SDK or later, included in Xcode 9 or later. Further, starting March 2019, all iOS apps submitted to the App Store must be built with the iOS 12.1 SDK or later, included in Xcode 10.1 or later." My apps are built from a third party but unfortunately they do not support anymore. Is there a way to rebuild the app using command line tools. I searched and tried to build using xcodebuild command but nothing seems to work. Is there an alternative?