Challenges of breaking changes in a design system

WHAT THIS TESTS The interviewer wants you to recognize that versioning a design system is as much a people problem as a code problem. Breaking changes ripple across many teams who did not ask for them.

A GOOD ANSWER COVERS On the technical side: use semantic versioning so a major bump clearly signals a breaking change, deprecate before removing with a grace period, ship codemods or migration scripts to automate updates, support coexistence of old and new versions during transition, and maintain a precise changelog. On the organizational side: communicate changes early and widely, write clear migration guides with before/after examples, offer office hours or hands-on help for large consumers, and negotiate realistic timelines since each team upgrades on its own cadence and priorities. Track adoption to know who is still behind. The hardest part is that you cannot force-upgrade everyone at once, so you must make migrating easy and low-risk.

COMMON WRONG ANSWERS Releasing a breaking major with no deprecation window, no codemod, and no announcement. Assuming a clean changelog alone is enough without migration tooling or support. Expecting all teams to upgrade immediately on your schedule.

LIKELY FOLLOW-UPS How do you decide what counts as a breaking change? How do you support teams that cannot upgrade in time? How do you balance system evolution against consumer stability?

ONE CONCRETE EXAMPLE You rename a Button prop, a breaking change. You first ship a minor that supports both old and new props with a deprecation warning, publish a codemod that rewrites old usages, write a migration guide, and announce the upcoming major with a timeline. Months later, after adoption dashboards show most teams migrated and you have offered help to stragglers, you release the major that removes the old prop, so no team is caught off guard.