diff --git a/docs/source/extending/handlers.rst b/docs/source/extending/handlers.rst
index f3bf87f270..09bfd04b25 100644
--- a/docs/source/extending/handlers.rst
+++ b/docs/source/extending/handlers.rst
@@ -115,7 +115,7 @@ following:
         Called when the extension is loaded.
 
         Args:
-            nb_server_app (NotebookWebApplication): handle to the Notebook webserver instance.
+            nb_server_app: handle to the Notebook webserver instance.
         """
         web_app = nb_server_app.web_app
         host_pattern = '.*$'
diff --git a/jupyter_server/serverapp.py b/jupyter_server/serverapp.py
index 46e9921fe2..8895a800b9 100755
--- a/jupyter_server/serverapp.py
+++ b/jupyter_server/serverapp.py
@@ -1050,6 +1050,16 @@ def _update_pylab(self, change):
         )
         self.exit(1)
 
+    notebook_dir = Unicode(
+        config=True,
+        help=_("DEPRECATED, use root_dir.")
+    )
+
+    @observe('notebook_dir')
+    def _update_notebook_dir(self, change):
+        self.log.warning(_("notebook_dir is deprecated, use root_dir"))
+        self.root_dir = change['new']
+
     root_dir = Unicode(config=True,
         help=_("The directory to use for notebooks and kernels.")
     )