OpenAI SDK v3.35.1 Released: Fixes WebSocket Byte Read Issue

According to the release record in the openai-sdks repository on GitHub, OpenAI SDK released version v3.35.1 on October 18, 2026. This is a minor version update focused on bug fixes, primarily addressing a byte read issue in the beta Realtime feature under the websockets 13 environment.

Version Update Overview

v3.35.1 is a patch release that introduces no new features and contains no breaking changes. The only change listed in the release notes is an entry under the Bug Fixes category: preserve beta Realtime byte reads on websockets 13, corresponding to PR #4102, with commit hash 5766349.

The commit was created with a GitHub-verified signature, with GPG key ID B5690EEEBB952194. The release artifacts include 2 asset files, marking this as a standard library version release process.

A patch release (the third digit in semantic versioning) typically contains only backward-compatible bug fixes, introduces no new features, and does not change public interfaces, so the upgrade risk is low. The PR number and commit hash in the release notes are key clues for tracing the source of changes: PR #4102 corresponds to the specific code change, and the commit hash 5766349 can be used to pinpoint the commit in the repository history. A GitHub-verified signature indicates that the commit was created by a maintainer holding the corresponding GPG private key, which can be used to confirm the authenticity of the code source and prevent supply chain tampering. The asset files in the release artifacts generally include the source package and the built distribution package, which are the direct source of what package managers pull and install.

Background: beta Realtime and websockets 13

The Realtime API is an interface provided by OpenAI for real-time interaction scenarios, and the beta module in the SDK provides wrapper support for it. WebSocket is one of the underlying transport methods for Realtime communication, and the websockets library in the Python ecosystem adjusted some behaviors in version 13.

When the underlying websockets was upgraded to 13, the SDK might exhibit inconsistent read behavior when handling byte-type messages. The goal of the fix in PR #4102 is to keep beta Realtime reading messages as bytes on websockets 13, avoiding data parsing anomalies caused by version differences. For developers who rely on Realtime for voice or streaming interaction, this type of compatibility fix directly affects connection stability.

The Realtime API is not a traditional request-response interface but a bidirectional streaming channel based on long-lived connections, used for low-latency scenarios such as voice dialogue and real-time transcription. It is typically carried over the WebSocket protocol at the underlying layer, and messages can be transmitted as text frames or binary frames. So-called "byte reads" refer to the SDK choosing to hand binary frames received from the WebSocket connection back to upper-layer logic as bytes rather than str. This difference may seem subtle, but it directly affects how messages are parsed: if handled as text, binary audio or event payloads may be incorrectly decoded or truncated. websockets 13 adjusted frame type and message reassembly behavior, so the SDK needs to explicitly preserve the byte read path to ensure that Realtime data flows as expected.

websockets is the most mainstream WebSocket client and server implementation in the Python ecosystem, used by a large number of async frameworks and SDKs as an underlying transport dependency. In version 13, the library tightened some API behaviors, for example making a stricter distinction in message types and the return form of the receive interface, which requires wrapper layers that depend on the old default behavior to explicitly adapt. For middleware layers such as SDKs, a minor version upgrade of the underlying library often does not trigger compile-time errors, but it may change data types at runtime, so compatibility fixes are usually implemented by explicitly specifying the read mode.

Developer Upgrade Recommendations

Since this is a patch-level update, the upgrade cost is low. Projects that use the beta Realtime feature and run on websockets 13 should prioritize upgrading to v3.35.1; if a project is pinned to an older websockets version and does not enable Realtime, this update has limited impact on existing behavior and can be followed up at a regular pace.

Before upgrading, it is recommended to verify message sending and receiving over Realtime connections in a test environment, confirm that the byte read path works properly, and then push to production. At the same time, pay attention to the combination matrix of SDK versions and websockets versions, and avoid upgrading multiple underlying dependencies at the same time, which could obscure the source of problems.

Conclusion

v3.35.1 is a small fix with a clear scope: without changing public interfaces, it resolves the byte read compatibility issue in beta Realtime on websockets 13. For integrations related to real-time communication, this type of patch is worth following up promptly.

One-line Summary

OpenAI SDK v3.35.1 is released, fixing the byte read compatibility issue in beta Realtime on websockets 13.

Paragraph Summary

OpenAI SDK released the v3.35.1 patch version on October 18, 2026. It contains only one bug fix, with no new features and no breaking changes. The fix preserves beta Realtime byte read behavior on websockets 13, corresponding to PR #4102; the commit has a GitHub-verified signature, and the release artifacts include 2 asset files. The article explains that the Realtime API relies on WebSocket transport, that websockets 13 behavior adjustments may cause inconsistent byte message reads, and provides upgrade advice: projects using beta Realtime and running on websockets 13 should prioritize upgrading, verify message sending and receiving in a test environment, and then push to production.