What does it mean that migration from old schema to new schema?

When you update a schema you must also update everything built on top of it.

Example: You revise your understanding of what 'productive' means — from hours worked to problems solved. But your daily planning system still tracks hours, your self-evaluation still rewards long sessions, and your team expectations still anchor to presence. One updated schema. Five downstream structures still running on the old version. Until you migrate them all, your new understanding fights your old infrastructure every day.

Try this: Pick one belief or mental model you've updated in the last year. Write it down as 'Old schema: X → New schema: Y.' Then list every decision, habit, relationship, or system that was built on the old schema. For each one, mark it: already migrated, needs migration, or can't migrate yet. You now have a migration plan.