This repo demonstrates a difference in XML Schema parsing, between version 3.4.5 and 4.0.0.

echo "3.4.5" > xmlschema-version.txt
./clean.sh
./run.sh

This ends with: IF YOU CAN READ THIS, THE XML FILE WAS VALIDATED AGAINS THE XML SCHEMA

echo "4.0.0" > xmlschema-version.txt
./clean.sh
./run.sh

This ends with exception raised by xmlschema when validating the schema in file xml-import.xsd.