zod changelog & breaking changes

v4.4.3

2026-05-04

⚠ Potential breaking changes

9195250cab0e7950efe39c3926d6c203b4b0a170 docs: remove Mintlify from bronze sponsors (churned)
b8dffe9e62f17e6571e6249d05cc5102b54d94e4 docs: remove Numeric and Speakeasy (2+ missed monthly cycles)

2026-05-01

⚠ Potential breaking changes

1373c85da9aeff704a9762d27bc58699618aefb7 docs: remove AI disclosure guidance
88015df8e25c44fb5385eb3ef28935119cd5edea fix(docs): drop deprecated `baseUrl` from tsconfig

2026-04-29

⚠ Potential breaking changes

2026-04-29

⚠ Potential breaking changes

Potentially breaking bug fixes
JSON Schema `$defs` entries no longer include redundant `id
CUID validation through `z.cuid()` has been tightened, and CUID v1 is now deprecated. Fixed in [#5880](https://github.com/colinhacks/zod/pull/5880).
Empty `z.union([])`, `z.xor([])`, and discriminated unions no longer crash at construction time. They construct and fail at parse time. Fixed in [#5869](https://github.com/colinhacks/zod/pull/5869).
Commit [`55747b3c`](https://github.com/colinhacks/zod/commit/55747b3cd05cd8b60b4f3d6a6348e2c508069c12) Remove deprecated downlevelIteration option ([#5684](https://github.com/colinhacks/zod/pull/5684)) by @RyanCavanaugh
Commit [`518f15dd`](https://github.com/colinhacks/zod/commit/518f15ddada3b5d959f4ff32b094789e2d85349a) Preprocess is not deprecated ([#5721](https://github.com/colinhacks/zod/pull/5721)) by @mxdvl
Commit [`476ae243`](https://github.com/colinhacks/zod/commit/476ae243e86344af08d6c396deed082e83d7d7e1) Tighten cuid() regex and deprecate CUID v1 ([#5880](https://github.com/colinhacks/zod/pull/5880)) by @colinhacks

2026-01-22

No breaking-change keywords detected in release notes.

2026-01-04

⚠ Potential breaking changes

21afffdb42ccab554036312e33fed0ea3cb8f982 [Docs] Update migration guide docs for deprecation of message (#5595)

2025-12-31

⚠ Potential breaking changes

2025-12-31

No breaking-change keywords detected in release notes.