Jupyter Notebook developers maintain the two most recently released major versions of Notebook. Currently, this is Notebook 5 and Notebook 6. Notebook 7 has been in alpha since March 2022. When Notebook 7 is generally available, we will no longer release new versions of Notebook 5, even in the case of security vulnerabilities.
If you are still using Notebook 5, please make plans to upgrade to Notebook 6 as soon as possible. Do not wait until Notebook 7 is available.