# Creating comms on Jupyterlab V4

**URL:** <https://discourse.jupyter.org/t/creating-comms-on-jupyterlab-v4/17397>\
**Category:** JupyterLab\
**Tags:** jupyterlab, how-to, help-wanted, notebook\
**Created:** [December 29, 2022, 5:55pm UTC](https://discourse.jupyter.org/t/creating-comms-on-jupyterlab-v4/17397 "2022-12-29T17:55:38Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![ragokan](https://yyz1.discourse-cdn.com/flex031/user_avatar/discourse.jupyter.org/ragokan/32/8200_2.png) [@ragokan](https://discourse.jupyter.org/u/ragokan)\
**Post date:** [December 29, 2022, 5:55pm UTC](https://discourse.jupyter.org/t/creating-comms-on-jupyterlab-v4/17397/1 "2022-12-29T17:55:38Z")

</div>

Hello, I want to create a comm for my extension to have communication with my kernel.  
But sadly, the backend gives this error:  
IPKernelApp] WARNING | Unknown message type: ‘comm\_open’.

For frontend part, I also am not able to use a proper way to have a comm. I tried this: [Comms — Jupyter Notebook 6.5.2 documentation](https://jupyter-notebook.readthedocs.io/en/stable/comms.html) but ‘Jupyter’ was undefined, so it was also not successful.