Thank you for your quick help! As a result of building using Xcode 11.7, I confirmed the following error. ld: library not found for -lstdc ++. 6 Upon examination, Xcode 10 and later no longer support this library. From this, it seems that the old apps that other companies are requesting are from old Xcode, which was created before I belonged to the company ... About this library, I was able to download the file from the following, so I applied the library to xcode according to the readme. https://github.com/Kila2/libstdc-.6.0.9.tbd As a result, the error disappeared, but there was a problem with the app ... Is there anything else I can do with Xcode 11? Or can Xcode 8 fix the error? Best Regard,