XCode 11 / Sierra Not Upgradeable 13" Mac Mid-2010

I want to upload a new version of my app to the app store
but the distribution processes is requiring me to upgrade to XCode 11 / iOS SDK 13 (Error Code ITMS-90725, "SDK Version Issue") and its a bit of a catch-22 situation.

I'm running a 13" Mac Mid-2010; High Sierra 10.13.6; XCode 10.1; NVIDIA GeForce 320M 256 MB graphics card; 500 GB SSD; 4 GB Ram.

I ran an update check on the Mac and checked the iOS documentation. Everything is up to date and there is not any pending update for iOS. XCode has a pending update but it shows incompatible with the current OS version.

So I need XCode 11 to release the app but to get that I need an OS upgrade which doesn't exist! I'm told by Apple support that I and out of luck and the machine is not updateable any longer. I'm stuck and can't release the new version of my app and have to toss the machine.
 
Why do I have to throw away this perfectly good machine??? Any ideas how I can make this work?

https://support.apple.com/en-us/HT210190

https://support.apple.com/en-us/HT208898



 
XCode 11 / Sierra Not Upgradeable 13" Mac Mid-2010
 
 
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