diff --git a/jupyter-config/jupyter_notebook_config.d/jupytext.json b/jupyter-config/jupyter_notebook_config.d/jupytext.json
index 56f59be4b..86608d7dc 100644
--- a/jupyter-config/jupyter_notebook_config.d/jupytext.json
+++ b/jupyter-config/jupyter_notebook_config.d/jupytext.json
@@ -1,5 +1,7 @@
 {
   "NotebookApp": {
-    "contents_manager_class": "jupytext.TextFileContentsManager"
+    "nbserver_extensions": {
+      "jupytext": true
+    }
   }
 }
diff --git a/jupytext/__init__.py b/jupytext/__init__.py
index b1ae6cdea..2528427dd 100644
--- a/jupytext/__init__.py
+++ b/jupytext/__init__.py
@@ -15,6 +15,22 @@ def __init__(self):
             raise self.err
 
 
+def load_jupyter_server_extension(app):  # pragma: no cover
+    """Use Jupytext's contents manager"""
+    # The server extension call is too late!
+    # The contents manager was set at NotebookApp.init_configurables
+
+    # Let's change the contents manager class
+    app.contents_manager_class = TextFileContentsManager
+
+    # And rerun the init steps from then to now
+    app.init_configurables()
+    app.init_components()
+    app.init_webapp()
+    app.init_terminals()
+    app.init_signal()
+
+
 def _jupyter_nbextension_paths():  # pragma: no cover
     """Allows commands like
      jupyter nbextension install --py jupytext
diff --git a/jupytext/version.py b/jupytext/version.py
index 9f46bf9d2..70e8be200 100644
--- a/jupytext/version.py
+++ b/jupytext/version.py
@@ -1,3 +1,3 @@
 """Jupytext's version number"""
 
-__version__ = '1.0.0-rc4'
+__version__ = '1.0.0-rc4+dev'