Yesterday we started seeing this error
Error: code 4107 (Please update iTMSTransporter to a newer version. (4107))
when running
/Applications/Xcode-12.1.app/Contents/Developer/usr/bin/altool --upload-app ...
We're using the latest non-RC Xcode and successfully uploaded using the same Xcode version last week.
Has anyone else encountered this error and/or found a solution?