pypi / jupytext
jupytext
What changed in jupytext 1, from its official release notes, upgrade guides and advisories. Sources checked 2026-10-24.
1 breaking5 security2 new APIs and options1 performance1 tooling6 fixes and other
See which of these apply to your code, ranked, in your agent:
npx @unstale/cli initjupytext 116 changes
Breaking changes 1
Paired paths from notebook formats metadata can no longer escape the working tree, including for absolute notebook paths.
Security 5
Custom light-format cell markers are matched literally, preventing regular-expression injection, parsing errors, and excessive processing time on crafted notebooks.
Custom light-format end-of-cell values are matched literally, preventing regular-expression injection, parsing errors, and excessive processing time on crafted notebooks.
Quarto conversions run in a private temporary directory, preventing another user from pre-creating the output file as a symlink.
The CLI ignores trusted cell metadata when the notebook signature is invalid, preventing paired text from making untrusted outputs trusted during synchronization.
Reuses secure (0600, mkstemp-backed) temporary files instead of closing and reopening them by name, removing unsafe permissions and a symlink-attack window on shared machines.
New APIs and options 2
Jupytext now supports the Jenner language.
A new custom_language_magics option is available.
Performance 1
Detecting IPython help/shell commands no longer takes quadratic time on lines made of whitespace.
Tooling 1
A development container is available to open with VS Code’s Dev Containers extension.
Fixes and other changes 6
Pairing works when a prefix root contains subdirectories.
A whitespace-only final line is preserved when reading and round-tripping the notebook.
Mermaid comments inside markdown cells are no longer mistaken for py:percent cell markers.
Menu entries name the file type again instead of saying “default.”
Guards access to languageInfo.extensions when kernel metadata is incomplete, preventing Python files from being shown with notebook icons.
YAML dumping now supports Unicode characters.