diff --git a/pyproject.toml b/pyproject.toml
index 9d5e51d50..921a73c4c 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -38,7 +38,7 @@ dependencies = [
     "jupyter_core>=4.11.0",
     "jupyter_server>=1.18,<2.0.0",
     "jupyterlab_server>=2.3.0,<3",
-    "nbclient>=0.4.0,<0.6",
+    "nbclient>=0.4.0,<0.7",
     "nbconvert>=6.4.5,<7",
     "traitlets>=5.0.3,<6",
     "websockets>=9.0",