Guidelines on API Changes

• Always try to maintain API compatibility.
• If an interface must be changed, try to maintain the old interface for at least one minor (eg. 0.10 → 0.11) version change and log deprecation warnings when it's used. Document the API change in TracDev/ApiChanges/<version>.
• If the old interface can't be maintained, document it as such in the appropriate TracDev/ApiChanges/<version> Wiki page.