Changes in IPython kernel



  • Kernelspec: ensure path is writable before writing kernel.json. (PR #593)
  • Add configure_inline_support and call it in the shell. (PR #590)



  • Rework wait_for_ready logic. (PR #578)


  • Revert “Fix stop_on_error_timeout blocking other messages in queue”. (PR #570)


  • Invalid syntax in ipykernel/ (PR #567)


5.4.0 is generally focused on code quality improvements and tornado asyncio compatibility.

  • Add github actions, bail on asyncio patch for tornado 6.1. (PR #564)
  • Start testing on Python 3.9. (PR #551)
  • Fix stack levels for ipykernel’s deprecation warnings and stop using some deprecated APIs. (PR #547)
  • Add env parameter to kernel installation (PR #541)
  • Fix stop_on_error_timeout blocking other messages in queue. (PR #539)
  • Remove most of the python 2 compat code. (PR #537)
  • Remove u-prefix from strings. (PR #538)



  • Only run Qt eventloop in the shell stream. (PR #531)


  • Fix QSocketNotifier in the Qt event loop not being disabled for the control channel. (PR #525)


  • Restore timer based event loop as a Windows-compatible fallback. (PR #523)


  • Fix #520: run post_execute and post_run_cell on async cells (PR #521)
  • Fix exception causes in (PR #516)
  • Make pdb on Windows interruptible (PR #490)


5.3.0 Adds support for Trio event loops and has some bug fixes.

  • Fix ipython display imports (PR #509)
  • Skip test_unc_paths if OS is not Windows (PR #507)
  • Allow interrupting input() on Windows, as part of effort to make pdb interruptible (PR #498)
  • Add Trio Loop (PR #479)
  • Flush from process even without newline (PR #478)



  • Handle system commands that use UNC paths on Windows (PR #500)
  • Add offset argument to seek in io test (PR #496)


5.2.0 Includes several bugfixes and internal logic improvements.

  • Produce better traceback when kernel is interrupted (PR #491)
  • Add InProcessKernelClient.control_channel for compatibility with jupyter-client v6.0.0 (PR #489)
  • Drop support for Python 3.4 (PR #483)
  • Work around issue related to Tornado with python3.8 on Windows (PR #480, PR #481)
  • Prevent entering event loop if it is None (PR #464)
  • Use shell.input_transformer_manager when available (PR #411)



5.1.4 Includes a few bugfixes, especially for compatibility with Python 3.8 on Windows.

  • Fix pickle issues when using inline matplotlib backend (PR #476)
  • Fix an error during kernel shutdown (PR #463)
  • Fix compatibility issues with Python 3.8 (PR #456, PR #461)
  • Remove some dead code (PR #474, PR #467)


5.1.3 Includes several bugfixes and internal logic improvements.

  • Fix comm shutdown behavior by adding a deleting option to close which can be set to prevent registering new comm channels during shutdown (:ghpull: 433, :ghpull: 435)
  • Fix Heartbeat._bind_socket to return on the first bind (:ghpull: 431)
  • Moved InProcessKernelClient.flush to DummySocket (:gphull: 437)
  • Don’t redirect stdout if nose machinery is not present (:ghpull: 427)
  • Rename to to avoid name conflicts on Python 3.6+ (:ghpull: 426)
  • Only generate kernelspec when installing or building wheel (:ghpull: 425)
  • Fix priority ordering of control-channel messages in some cases (PR #443)


5.1.2 fixes some socket-binding race conditions that caused testing failures in nbconvert.

  • Fix socket-binding race conditions (:ghpull: 412, :ghpull: 419)
  • Add a no-op flush method to DummySocket and comply with stream API (:ghpull: 405)
  • Update kernel version to indicate kernel v5.3 support (:ghpull: 394)
  • Add testing for upcoming Python 3.8 and PEP 570 positional parameters (:ghpull: 396, :ghpull: 408)


5.1.1 fixes a bug that caused cells to get stuck in a busy state.

  • Flush after sending replies (PR #390)


5.1.0 fixes some important regressions in 5.0, especially on Windows.

5.1.0 on GitHub

  • Fix message-ordering bug that could result in out-of-order executions, especially on Windows (PR #356)
  • Fix classifiers to indicate dropped Python 2 support (PR #354)
  • Remove some dead code (PR #355)
  • Support rich-media responses in inspect_requests (tooltips) (PR #361)



5.0.0 on GitHub

  • Drop support for Python 2. ipykernel 5.0 requires Python >= 3.4
  • Add support for IPython’s asynchronous code execution (PR #323)
  • Update release process in (PR #339)


4.10 on GitHub

  • Fix compatibility with IPython 7.0 (PR #348)
  • Fix compatibility in cases where sys.stdout can be None (PR #344)



4.9.0 on GitHub

  • Python 3.3 is no longer supported (PR #336)
  • Flush stdout/stderr in KernelApp before replacing (PR #314)
  • Allow preserving stdout and stderr in KernelApp (PR #315)
  • Override writable method on OutStream (PR #316)
  • Add metadata to help display matplotlib figures legibly (PR #336)



4.8.2 on GitHub

  • Fix compatibility issue with qt eventloop and pyzmq 17 (PR #307).


4.8.1 on GitHub

  • set zmq.ROUTER_HANDOVER socket option when available to workaround libzmq reconnect bug (PR #300).
  • Fix sdists including absolute paths for kernelspec files, which prevented installation from sdist on Windows (PR #306).


4.8.0 on GitHub

  • Cleanly shutdown integrated event loops when shutting down the kernel. (PR #290)
  • %gui qt now uses Qt 5 by default rather than Qt 4, following a similar change in terminal IPython. (PR #293)
  • Fix event loop integration for asyncio when run with Tornado 5, which uses asyncio where available. (PR #296)



4.7.0 on GitHub

  • Add event loop integration for asyncio.
  • Use the new IPython completer API.
  • Add support for displaying GIF images (mimetype image/gif).
  • Allow the kernel to be interrupted without killing the Qt console.
  • Fix is_complete response with cell magics.
  • Clean up encoding of bytes objects.
  • Clean up help links to use https and improve display titles.
  • Clean up ioloop handling in preparation for tornado 5.



4.6.1 on GitHub

  • Fix eventloop-integration bug preventing Qt windows/widgets from displaying with ipykernel 4.6.0 and IPython ≥ 5.2.
  • Avoid deprecation warnings about naive datetimes when working with jupyter_client ≥ 5.0.


4.6.0 on GitHub

  • Add to API DisplayPublisher.publish two new fully backward-compatible keyword-args:

    • update: bool
    • transient: dict
  • Support new transient key in display_data messages spec for publish. For a display data message, transient contains data that shouldn’t be persisted to files or documents. Add a display_id to this transient dict by display(obj, display_id=...)

  • Add ipykernel_launcher module which removes the current working directory from sys.path before launching the kernel. This helps to reduce the cases where the kernel won’t start because there’s a (or similar) module in the current working directory.

  • Add busy/idle messages on IOPub during processing of aborted requests

  • Add active event loop setting to GUI, which enables the correct response to IPython’s is_event_loop_running_xxx

  • Include IPython kernelspec in wheels to reduce reliance on “native kernel spec” in jupyter_client

  • Modify OutStream to inherit from TextIOBase instead of object to improve API support and error reporting

  • Fix IPython kernel death messages at start, such as “Kernel Restarting…” and “Kernel appears to have died”, when parent-poller handles PID 1

  • Various bugfixes



4.5.2 on GitHub

  • Fix bug when instantiating Comms outside of the IPython kernel (introduced in 4.5.1).


4.5.1 on GitHub

  • Add missing stream parameter to overridden getpass()
  • Remove locks from iopub thread, which could cause deadlocks during debugging
  • Fix regression where KeyboardInterrupt was treated as an aborted request, rather than an error
  • Allow instantiating Comms outside of the IPython kernel


4.5 on GitHub

  • Use figure.dpi instead of savefig.dpi to set DPI for inline figures
  • Support ipympl matplotlib backend (requires IPython update as well to fully work)
  • Various bugfixes, including fixes for output coming from threads, and input() when called with non-string prompts, which stdlib allows.



4.4.1 on GitHub

  • Fix circular import of matplotlib on Python 2 caused by the inline backend changes in 4.4.0.


4.4.0 on GitHub

  • Use MPLBACKEND environment variable to tell matplotlib >= 1.5 use use the inline backend by default. This is only done if MPLBACKEND is not already set and no backend has been explicitly loaded, so setting MPLBACKEND=Qt4Agg or calling %matplotlib notebook or matplotlib.use('Agg') will take precedence.
  • Fixes for logging problems caused by 4.3, where logging could go to the terminal instead of the notebook.
  • Add --sys-prefix and --profile arguments to ipython kernel install
  • Allow Comm (Widget) messages to be sent from background threads.
  • Select inline matplotlib backend by default if %matplotlib magic or matplotlib.use() are not called explicitly (for matplotlib >= 1.5).
  • Fix some longstanding minor deviations from the message protocol (missing status: ok in a few replies, connect_reply format).
  • Remove calls to NoOpContext from IPython, deprecated in 5.0.



  • Use a nonempty dummy session key for inprocess kernels to avoid security warnings.


  • Fix Windows Python 3.5 incompatibility caused by faulthandler patch in 4.3


4.3.0 on GitHub

  • Publish all IO in a thread, via IOPubThread. This solves the problem of requiring sys.stdout.flush() to be called in the notebook to produce output promptly during long-running cells.
  • Remove references to outdated IPython guiref in kernel banner.
  • Patch faulthandler to use sys.__stderr__ instead of forwarded sys.stderr, which has no fileno when forwarded.
  • Deprecate some vestiges of the Big Split: - ipykernel.find_connection_file() is deprecated. Use jupyter_client.find_connection_file() instead. - Various pieces of code specific to IPython parallel are deprecated in ipykernel and moved to ipyparallel.



4.2.2 on GitHub

  • Don’t show interactive debugging info when kernel crashes
  • Fix handling of numerical types in json_clean
  • Testing fixes for output capturing


4.2.1 on GitHub

  • Fix default display name back to “Python X” instead of “pythonX”


4.2 on GitHub

  • Support sending a full message in initial opening of comms (metadata, buffers were not previously allowed)
  • When using ipython kernel install --name to install the IPython kernelspec, default display-name to the same value as --name.



4.1.1 on GitHub

  • Fix missing ipykernel.__version__ on Python 2.
  • Fix missing target_name when opening comms from the frontend.


4.1 on GitHub

  • add ipython kernel install entrypoint for installing the IPython kernelspec
  • provisional implementation of comm_info request/reply for msgspec v5.1


4.0 on GitHub

4.0 is the first release of ipykernel as a standalone package.