Sources:

1. Reactive Manifesto
2. Reactive Principles

Key properties of a Reactive system:

• responsive — responds in a reasonable time if possible,
• resilient — stays responsive even when failures occur,
• elastic — stays responsive under varying load,
• message-driven — relies on asynchronous communication.

Source: Evolving HTTP APIs

1. Compatible versions shouldn't cause any adjustments (shouldn't change versions).
2. Avoid major / incompatible versions.
3. Be backward-compatible, but still limiting the impact. New version requires everyone to adapt, so keeping the same version with some adjustments might make more sense from effort perspective.

Sources:

1. Self-contained Systems: A Different Approach to Microservices
2. Self-Contained Systems

in progress