---
title: "hpack Breaking Changes on PyPI | Since.dev"
description: "What each hpack release removed, renamed or changed: 6 breaking changes in 1 version on PyPI, each with its source."
canonical_url: https://since.dev/packages/pypi/hpack
last_updated: 2026-06-23
---

# hpack breaking changes

Every breaking API change we have recorded in hpack on PyPI: 6 breaking changes in 1 version. Below are its newest version, removals and renames first, each with its source.

Newest change June 23, 2026

## 4.2.0

6 breaking changes, first published June 23, 2026.

- **Removed**  

PyPy 3.9 is no longer supported. Users on PyPy 3.9 must stay on hpack 4.1.0 or upgrade their PyPy version. [github.com](https://github.com/python-hyper/hpack/blob/v4.2.0/CHANGELOG.rst)
- **Removed**  

Python 3.9 is no longer supported. Users on Python 3.9 must stay on hpack 4.1.0 or upgrade their Python version. [github.com](https://github.com/python-hyper/hpack/blob/v4.2.0/CHANGELOG.rst)
- **Behavior changed**  

Variable integer decoding now rejects values larger than uint32, which previously decoded without error. Code relying on larger values will now fail. [github.com](https://github.com/python-hyper/hpack/blob/v4.2.0/CHANGELOG.rst)
- **Signature changed** `hpack.hpack.decode_huffman`  

Was def decode_huffman(huffman_string: bytes | bytearray | None) -> bytes; now def decode_huffman(huffman_string: bytes | bytearray | memoryview | None) -> bytes. [pypi.org](https://pypi.org/project/hpack/4.2.0/)
- **Signature changed** `hpack.hpack.decode_integer`  

Was def decode_integer(data: bytes, prefix_bits: int) -> tuple\[int, int\]; now def decode_integer(data: bytes | memoryview, prefix_bits: int) -> tuple\[int, int\]. [pypi.org](https://pypi.org/project/hpack/4.2.0/)
- **Signature changed** `hpack.huffman_table.decode_huffman`  

Was def decode_huffman(huffman_string: bytes | bytearray | None) -> bytes; now def decode_huffman(huffman_string: bytes | bytearray | memoryview | None) -> bytes. [pypi.org](https://pypi.org/project/hpack/4.2.0/)

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