Submit app via Xcode 10 GM got - ERROR ITMS-90733: "The binary you uploaded was invalid."

I'm getting this as well. Very frustrating.

We have the same problem

Thanks, as "raymo" pointed out, I also have "i386" inside watchOS extension, removed "i386" and also need to add "arm64_32"(this is impotrtant, without this, will still get invalid binary). Now my binary is validated and ready to upload.

Frustrating. Why don't they flag these problems way earlier? I was submitting betas no problem and as soon as you get to the end, you get some obtuse error which you can't look up or figure out how to fix easily. Thanks for the fix - I assume it works. Will it affect what watches the app extension will run on?

Yes, indeed frustrated. Looks like every time new Xcode/iOS/Device release there will be some here and there issue. Good thing we have this forum to ask and people can answer and help.

Note: to be able to compile and run on WatchOS simulator, need to temporarily add "i386".

My app just got approved so I'll assume it should be fine for new Watch devices. At least I can run fine on new Watch Series 4 device.