Changes following the review

README.md

@@ -28,6 +28,13 @@ Anyone in the community can jump in and help with these activities at any time.
 grant additional permissions (e.g., ability to merge PRs) to anyone who shows an on-going interest
 in working on the project.
 
+## Jupyter Notebook Deprecation Notice
+
+Following [Jupyter Notebook notice](https://github.com/jupyter/notebook#notice), we encourage users to transition to JupyterLab.
+This can be done by passing the environment variable `JUPYTER_ENABLE_LAB=yes` at container startup, 
+more information in the [documentation](https://jupyter-docker-stacks.readthedocs.io/en/latest/using/common.html).
+This change is followed in the issue [#1217](https://github.com/jupyter/docker-stacks/issues/1217).
+
 ## Quick Start
 
 You can try a

base-notebook/start-notebook.sh

@@ -12,12 +12,9 @@ fi
 if [[ ! -z "${JUPYTERHUB_API_TOKEN}" ]]; then
     # launched by JupyterHub, use single-user entrypoint
     exec /usr/local/bin/start-singleuser.sh "$@"
-elif [[ ! -z "${JUPYTER_ENABLE_NB}" ]]; then
-    echo "WARN: We encourage users to transition to JupyterLab, Notebook support could be removed"
-    . /usr/local/bin/start.sh $wrapper jupyter notebook "$@"
-else
-    if [[ ! -z "${JUPYTER_ENABLE_LAB}" ]]; then
-        echo "WARN: The JUPYTER_ENABLE_LAB environment variable is not required anymore"
-    fi
+elif [[ ! -z "${JUPYTER_ENABLE_LAB}" ]]; then
     . /usr/local/bin/start.sh $wrapper jupyter lab "$@"
+else
+    echo "WARN: Jupyter Notebook deprecation notice https://github.com/jupyter/notebook#notice."
+    . /usr/local/bin/start.sh $wrapper jupyter notebook "$@"
 fi

base-notebook/test/test_start_script.py

@@ -10,9 +10,8 @@ LOGGER = logging.getLogger(__name__)
 @pytest.mark.parametrize(
     "env,expected_server",
     [
-        (["JUPYTER_ENABLE_NB=yes"], "notebook"),
         (["JUPYTER_ENABLE_LAB=yes"], "lab"),
-        (None, "lab"),
+        (None, "notebook"),
     ],
 )
 def test_start_notebook(container, http_client, env, expected_server):
@@ -28,10 +27,7 @@ def test_start_notebook(container, http_client, env, expected_server):
     assert (
         f"Executing the command: jupyter {expected_server}" in logs
     ), f"Not the expected command (jupyter {expected_server}) was launched"
-    if env:
     # Checking warning messages
-        if "JUPYTER_ENABLE_LAB=yes" in env:
-            msg = "WARN: The JUPYTER_ENABLE_LAB environment variable is not required anymore"
-        elif "JUPYTER_ENABLE_NB=yes" in env:
-            msg = "WARN: We encourage users to transition to JupyterLab, Notebook support could be removed"
+    if not env:
+        msg = "WARN: Jupyter Notebook deprecation notice https://github.com/jupyter/notebook#notice."
         assert msg in logs, f"Expected warning message {msg} not printed"