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Changelog

This documents notable changes in IJulia.jl. The format is based on Keep a Changelog.

Unreleased

v1.31.1 - 2025-10-20

Added

  • Added support for JSON v1 (#1197).

Fixed

  • Fixed support for 32bit systems (#1196).

Changed

  • Improved precompilation for the PythonCall.jl extension, if ipywidgets is installed in the Python environment then it will be used to execute a simple workload (#1199).

v1.31.0 - 2025-10-13

Added

  • Implemented a PythonCall.jl extension to support interactive ipywidgets and matplotlib widgets in Julia (#1190).
  • Added support for buffers in the Jupyter messaging protocol (#1190).

v1.30.6 - 2025-10-06

Fixed

  • It's now possible to register hooks at any time, even if an IJulia kernel is not running (#1188). This was accidentally broken in v1.30.

Changed

  • Implemented lazy loading for Conda.jl (#1187), which shaves off about 60% of the load time (~0.21s to ~0.08s on Julia 1.12).

v1.30.5 - 2025-10-03

Fixed

  • Fixed a major performance regression in message hashing from the switch to SHA.jl in v1.29.1, which particularly affected things like plot/dataframe outputs (#1185).

v1.30.4 - 2025-09-08

Fixed

  • Fixed usage of In and Out so that they actually contain the cell history instead of just being empty (#1182). This was accidentally broken in v1.30.0.

v1.30.3 - 2025-09-02

Fixed

  • Modified the internal IJuliaStdio struct to be deepcopy-able, which was inadvertently broken in v1.30.0 (#1180).

v1.30.2 - 2025-08-29

Changed

  • Implemented lazy loading for Pkg.jl (#1177), which significantly cuts down the load time (~0.75s to ~0.25s on Julia 1.11). Also made various other improvements to precompilation and inference to improve TTFX.

v1.30.1 - 2025-08-27

Fixed

  • Added the default value kernel=_default_kernel to the function set_max_stdio, which fixes a breaking change introduced in v1.30.0 (#1178).

v1.30.0 - 2025-08-24

Added

Changed

  • IJulia was completely refactored to minimize global state (#1145). This allows for better testing (for the first time we can test kernel execution) and for executing precompilation workloads. We've tried to avoid any breaking changes but it's possible that some packages may be relying on internals that have changed. If you have any problems with this release please open an issue on Github so we can help.
  • history() now prints each entry on a new line (#1145).

v1.29.2 - 2025-07-29

Fixed

  • Fixed a typo in the tooltip lookup code (#1171).

v1.29.1 - 2025-07-26

Changed

  • Improved the token-finding functionality to return more accurate tooltips when Shift + Tab is pressed (#847).
  • IJulia switched from using MbedTLS.jl to the SHA.jl stdlib. This should not change anything for users except that now only SHA message digests are supported instead of e.g. MD5, and Jupyter uses SHA256 by default (#1170).

v1.29.0 - 2025-06-13

Added

Fixed

  • Fixed handling of the Jupyter process in notebook() and jupyterlab() when Ctrl + C'ing to shutdown the server, now any running kernels will be cleanly shutdown as well (#1165).

v1.28.1 - 2025-06-02

Fixed

  • Fixed a deadlock in the shutdown_request handler that would cause the kernel to hang when exiting (#1163).

v1.28.0 - 2025-06-01

Added

  • notebook() and jupyterlab() now support a verbose keyword argument to echo output from Jupyter to the terminal, which can be useful when debugging kernels (#1157).

Changed

  • IJulia no longer uses a standalone kernel.jl file to launch the kernel, it instead calls a function inside the IJulia module. This means that kernel specs don't use absolute paths anymore and it's not necessary to rebuild IJulia after updating the package (#1158).
  • Colors in stacktraces are now displayed properly in Jupyter (#1161).

Fixed

  • The Julia major and minor version are no longer appended to a custom specname in installkernel(). The default specname that derives from name and appends the Julia version remains unchanged (#1154).
  • Fixed adding multiple packages in Pkg mode (#1160).
  • Fixed an edge-case in inspection requests that would cause autocompletion to not work properly (#1159).

v1.27.0 - 2025-04-01

Added

Fixed

  • The internal heartbeat thread will now shut down cleanly (#1135, #1144, #1150). This should prevent segfaults upon exit.
  • Various fixes to the messaging code to be compliant with Jupyter (#1138, #1150).
  • Improved threadsafety of the IO-handling code so that it should be safe to call flush() concurrently (#1149).