6.4.5. Interoperability

This section discusses interoperability considerations for the URN namespace. It needs to explain:

1. Relationship with other identifier systems: Whether it interoperates with other URI schemes or identifier systems
2. Encoding and character set issues: How to handle internationalized characters
3. Version compatibility: If the namespace may evolve, how to maintain compatibility
4. Cross-platform considerations: Use of URNs on different systems and platforms
5. Known interoperability limitations: Any factors that may affect interoperability

Clear interoperability requirements help ensure widespread adoption and effective use of URNs.