What backward-compatible XSD changes can be made?

问题

How can I make changes to an XML Schema for a REST interface without impacting consuming applications (if they do not upgrade)?

回答1:

1. Just don't alter the existing schema and structures to ensure backward compatibility.
2. Only add optional elements and attributes as required to extend the functionality.
3. Always version your services - either URL way or Content-Type way! This is to ensure maintainability.

回答2:

Here are some examples of request XSD changes that you can and cannot do to maintain backward compatibility with the previous interface version.

Can do

1. Add optional elements or attributes.
2. Change requiredness from required to optional.
3. Add values to enumerations.

Cannot do

1. Add or delete required elements or attributes.
2. Change element or attribute names.
3. Change requiredness from optional to required.
4. Remove values from enumerations.

来源：https://stackoverflow.com/questions/30198785/what-backward-compatible-xsd-changes-can-be-made