diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9166759234..fd22088a96 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -14,6 +14,22 @@ Use `pip install pip --upgrade` to upgrade pip. Check pip version with
 
 <!-- <START NEW CHANGELOG ENTRY> -->
 
+## 6.5.6
+
+([Full Changelog](https://github.com/jupyter/notebook/compare/v6.5.5...566860bf159843f95d5f813c0baa9785014fee55))
+
+### Bugs fixed
+
+- fix traitlets warning->error on 6.5.x [#7051](https://github.com/jupyter/notebook/pull/7051) ([@minrk](https://github.com/minrk))
+
+### Contributors to this release
+
+([GitHub contributors page for this release](https://github.com/jupyter/notebook/graphs/contributors?from=2023-07-27&to=2023-09-19&type=c))
+
+[@blink1073](https://github.com/search?q=repo%3Ajupyter%2Fnotebook+involves%3Ablink1073+updated%3A2023-07-27..2023-09-19&type=Issues) | [@defjaf](https://github.com/search?q=repo%3Ajupyter%2Fnotebook+involves%3Adefjaf+updated%3A2023-07-27..2023-09-19&type=Issues) | [@echarles](https://github.com/search?q=repo%3Ajupyter%2Fnotebook+involves%3Aecharles+updated%3A2023-07-27..2023-09-19&type=Issues) | [@github-actions](https://github.com/search?q=repo%3Ajupyter%2Fnotebook+involves%3Agithub-actions+updated%3A2023-07-27..2023-09-19&type=Issues) | [@jtpio](https://github.com/search?q=repo%3Ajupyter%2Fnotebook+involves%3Ajtpio+updated%3A2023-07-27..2023-09-19&type=Issues) | [@kevin-bates](https://github.com/search?q=repo%3Ajupyter%2Fnotebook+involves%3Akevin-bates+updated%3A2023-07-27..2023-09-19&type=Issues) | [@minrk](https://github.com/search?q=repo%3Ajupyter%2Fnotebook+involves%3Aminrk+updated%3A2023-07-27..2023-09-19&type=Issues) | [@prof-lupin](https://github.com/search?q=repo%3Ajupyter%2Fnotebook+involves%3Aprof-lupin+updated%3A2023-07-27..2023-09-19&type=Issues) | [@shaneknapp](https://github.com/search?q=repo%3Ajupyter%2Fnotebook+involves%3Ashaneknapp+updated%3A2023-07-27..2023-09-19&type=Issues) | [@takluyver](https://github.com/search?q=repo%3Ajupyter%2Fnotebook+involves%3Atakluyver+updated%3A2023-07-27..2023-09-19&type=Issues) | [@Zsailer](https://github.com/search?q=repo%3Ajupyter%2Fnotebook+involves%3AZsailer+updated%3A2023-07-27..2023-09-19&type=Issues)
+
+<!-- <END NEW CHANGELOG ENTRY> -->
+
 ## 6.5.5
 
 ([Full Changelog](https://github.com/jupyter/notebook/compare/v6.5.4...fe35f939b5a2c256cbc6822a60ea728d6f5d4251))
@@ -32,8 +48,6 @@ Use `pip install pip --upgrade` to upgrade pip. Check pip version with
 
 [@andrii-i](https://github.com/search?q=repo%3Ajupyter%2Fnotebook+involves%3Aandrii-i+updated%3A2023-04-06..2023-07-27&type=Issues) | [@brichet](https://github.com/search?q=repo%3Ajupyter%2Fnotebook+involves%3Abrichet+updated%3A2023-04-06..2023-07-27&type=Issues) | [@echarles](https://github.com/search?q=repo%3Ajupyter%2Fnotebook+involves%3Aecharles+updated%3A2023-04-06..2023-07-27&type=Issues) | [@github-actions](https://github.com/search?q=repo%3Ajupyter%2Fnotebook+involves%3Agithub-actions+updated%3A2023-04-06..2023-07-27&type=Issues) | [@henryiii](https://github.com/search?q=repo%3Ajupyter%2Fnotebook+involves%3Ahenryiii+updated%3A2023-04-06..2023-07-27&type=Issues) | [@jtpio](https://github.com/search?q=repo%3Ajupyter%2Fnotebook+involves%3Ajtpio+updated%3A2023-04-06..2023-07-27&type=Issues) | [@krassowski](https://github.com/search?q=repo%3Ajupyter%2Fnotebook+involves%3Akrassowski+updated%3A2023-04-06..2023-07-27&type=Issues) | [@parmentelat](https://github.com/search?q=repo%3Ajupyter%2Fnotebook+involves%3Aparmentelat+updated%3A2023-04-06..2023-07-27&type=Issues) | [@RRosio](https://github.com/search?q=repo%3Ajupyter%2Fnotebook+involves%3ARRosio+updated%3A2023-04-06..2023-07-27&type=Issues) | [@tonyfast](https://github.com/search?q=repo%3Ajupyter%2Fnotebook+involves%3Atonyfast+updated%3A2023-04-06..2023-07-27&type=Issues) | [@yuvipanda](https://github.com/search?q=repo%3Ajupyter%2Fnotebook+involves%3Ayuvipanda+updated%3A2023-04-06..2023-07-27&type=Issues)
 
-<!-- <END NEW CHANGELOG ENTRY> -->
-
 ## 6.5.4
 
 ([Full Changelog](https://github.com/jupyter/notebook/compare/v6.5.3...428e00bef821acb42f13843fb2949d225d081d56))
diff --git a/notebook/_version.py b/notebook/_version.py
index 9016d2744a..80d9d77887 100644
--- a/notebook/_version.py
+++ b/notebook/_version.py
@@ -5,7 +5,7 @@
 import re
 
 # Version string must appear intact for tbump versioning
-__version__ = '6.5.5'
+__version__ = '6.5.6'
 
 # Build up version_info tuple for backwards compatibility
 pattern = r'(?P<major>\d+).(?P<minor>\d+).(?P<patch>\d+)(?P<rest>.*)'
diff --git a/pyproject.toml b/pyproject.toml
index 001b222bf8..edaf6c8ce2 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -16,7 +16,7 @@ before-build-python = ["pip install babel", "npm install -g po2json"]
 ignore-glob = ["docs/source/examples/Notebook/Working With Markdown Cells.ipynb", "docs-translations/**/README.md", "docs/source/contributing.rst", "docs/source/examples/Notebook/JavaScript Notebook Extensions.ipynb", "CHANGELOG.md", "notebook/static/components/**/*.*"]
 
 [tool.tbump.version]
-current = "6.5.5"
+current = "6.5.6"
 regex = '''
   (?P<major>\d+)\.(?P<minor>\d+)\.(?P<patch>\d+)
   ((?P<channel>a|b|rc|.dev)(?P<release>\d+))?