Submitting apps to the App Store with Dynamic Libraries

I was trying to submit a proof of concept app to the app store for TestFlight distribution. Submission failed.
Looked up Mapbox to see if there was a new version. No.
Looked up Mapbox to see if I was missing something in their instructions. No
A quick google search, lead me to a stack overflow post, which linked to another, which linked to this: Stripping Unwanted Architectures From Dynamic Libraries In Xcode
Copy, paste,

(might need to follow step 0 from here)
Archive, submit.
Upload Successful