Migrating to Requests v2.34.2
Version v2.34.2 introduces 2 breaking changes. This guide details how to update your code.
Released: 5/14/2026
⚠️ Check Your Code
If you use any of these symbols, you need to read this guide:
Request.headersBreaking Changes
●Issue #1
The type hint for the `headers` input has been reverted to `Mapping`. Code relying on `MutableMapping` or inferred dict types for `Request.headers` might experience issues if they attempt to use methods like `.update()` directly, as the type is now more strictly enforced as immutable.
●Issue #2
Users calling `Request.headers.update()` may need to narrow typing in their code to satisfy the new `Mapping` type constraint.
Migration Steps
- 1If you were relying on mutable dictionary behavior for `Request.headers`, ensure your type annotations reflect the expected `Mapping` type or use explicit casting if mutation is necessary.
Release Summary
This patch reverts the type hint for the `headers` input back to `Mapping` to resolve invariance issues, which may require minor type adjustments for users modifying request headers.
Need More Details?
View the full release notes and all changes for Requests v2.34.2.
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