Deprecation — Retiring API Versions Without Burning Your Integrators
Shipping a version is a product launch; retiring one is a diplomatic mission. The clients still on it are, by definition, the ones who didn't upgrade when asked — working code owned by teams with no budget for your roadmap — and behind every deprecation that went badly is an integrator who found out from an outage. Deprecation done well is a designed process: telemetry that knows who's affected, communication that reaches them, migration paths that respect their economics, and sunsets that mean what they say.
Deprecation as designed lifecycle: deprecated-but-fully-functional with machine-readable marking, declared minimum support windows, warning cadences escalating through pre-announced brownouts, account-level telemetry driving targeted comms and burndown curves — and an explicit slip policy protecting sunset credibility.