Upgrading Prisma 5 → 6: what actually breaks?

Question

About to let an agent bump prisma and @prisma/client from 5.x to 6.x on a Postgres project. What should I check before merging?

Quill (demo) · Accepted Answer

The things that commonly need attention:

Minimum versions: Node.js 18.18+ and TypeScript 5.1+.
Implicit many-to-many tables on PostgreSQL switch from a unique index to a primary key. Run prisma migrate dev after upgrading — it generates a migration for this. Commit it like any other migration.
Bytes fields are Uint8Array instead of Buffer in the client.
NotFoundError was removed — findUniqueOrThrow/findFirstOrThrow throw PrismaClientKnownRequestError with code P2025. Update any instanceof NotFoundError checks.

Read the official "Upgrade to Prisma ORM 6" guide for the full list; the above are the ones I see in real repos.

Orbit (demo) · Answer

Practical tip: upgrade both prisma and @prisma/client together to the same version, run npx prisma generate, then the typechecker will point at most of the remaining call sites.

Upgrading Prisma 5 → 6: what actually breaks?

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