i have the same issue,so wha are we gonna do?i didnt understand 
ERROR ITMS-90534: “Invalid Toolchain. New apps and app updates must be built with the public (GM) versions of Xcode 6 or later, OS X, and iOS SDK or later. Don’t submit apps built with beta software including beta OS X builds.”
What version of Corona SDK are you running?
What version of Xcode do you have installed?
Xcode version 7.3(7D175)
corona ver 2016.2830(2016.2.18)
Update your Corona SDK to the latest public build (2016.2906)
i did update last night, but still have the same error
Are you building for iOS or OS X?
Are you running a beta version of OS X?
no it s for iOS and is not beta version
Also i have another question about admob in corona sdk for my another android app,that how can i implement the admob ads
An interrogator will make a problem be fixed, and questions.
To : [member=‘jostejo.ca’]
Please write in the environment that you are using it first.
While it’s a question, please don’t shift to a different problem.
Because it should be a help to the person who saw later here.
When a problem is different, please distribute a thread.
To : [member=‘Mamutz31’]
That’s a little different in problem.
A problem is that an update couldn’t be performed.
First OS reboot.
CoronaSDK Please clap an application in a trash can.
After a OS reboot, a trash can is emptied.
New coronaSDK, please try reinstallation.
2-for now i gave up with iOS because i made another app and submitted but seems they have issue with my upload even it s not from corona sdk
Are 2 users an identical person?
First I think it’s taking to keep CoronaSDK in the latest.
The problem of Admod is completely the another question, so please question by other boards.
If you have a question about AdMob, Go to the proper forum:
https://forums.coronalabs.com/forum/545-monetization-in-app-purchases-ads-etc/
And click on “Start a New Topic”. What you’re doing is called “Hijacking the thread” and is against the forum rules. People will come to this thread to read about Application Loader issues and be upset to read about AdMob. People trying to find out about AdMob will miss the thread.
As for the error, somewhere along the way, there is something “beta” being detected. 2830 had a beta 9.3 SDK as an option along with 9.2 production. 2906, the latest public build only has 9.3 production. If you’re using 2906, then that means you may have a beta version of Xcode 9.3 installed. It’s possible to have multiple Xcode’s installed. I would make sure that you clear your computer of all versions of Xcode and then install from the Mac App Store.
You are the only one currently experiencing this issue so it has to be a setup issue on your computer.
Rob
appreciate your very quick response and apologize for 2 irrelevant question, I removed them
regarding to main issue, yes i got the same error and ill do your advise as soon as i can .
how to update corona in xcode?? How do I know which version of corona is installed in my xcode?? Thanks
Corona SDK is a separate product from Xcode. Corona SDK uses Xcode’s utilities to build your app, but the Xcode doesn’t know or need to know about Corona.
To upgrade Corona, simply download the latest version (public of daily build). Double click on the file that downloaded. Since you’re asking about Xcode, I’m assuming you’re on a Mac. This file will be a .dmg file. It will open a window and you simply drag the Corona Icon to the Applications Folder Icon. If you’re using public builds, it will write over the previous version. If you’re using daily builds it will create a new application in /Applications named after the build number, for instance CoronaSDK.2934. That way you can test different daily builds with out overwriting the public build. Then simply run the Corona Simulator from either the public build folder (if that’s what you updated) or from the new folder of the daily build.
Corona generally requires you to also keep your Xcode up to date. When you go to build in Corona (CMD-B) the dialog box will list an iOS SDK. Mine currently lists 9.3. We do change this from time to time as Apple issues new versions. Your Xcode should match this version, but it’s two numbers behind. For instance if you’re using a Corona SDK that is using iOS 9.3, you need Xcode 7.3 installed.
Later today, I expect Apple to release iOS 10 to the world along with Xcode 8. When we turn on iOS 10 as an option, if you want to use that you would need to install Xcode 8 first.
Rob