diff --git a/jupyterhub/apihandlers/auth.py b/jupyterhub/apihandlers/auth.py
index aefc98bf..a1b148b0 100644
--- a/jupyterhub/apihandlers/auth.py
+++ b/jupyterhub/apihandlers/auth.py
@@ -26,7 +26,7 @@ class CookieAPIHandler(APIHandler):
     def get(self, cookie_name, cookie_value=None):
         cookie_name = quote(cookie_name, safe='')
         if cookie_value is None:
-            self.log.warn("Cookie values in request body is deprecated, use `/cookie_name/cookie_value`")
+            self.log.warning("Cookie values in request body is deprecated, use `/cookie_name/cookie_value`")
             cookie_value = self.request.body
         else:
             cookie_value = cookie_value.encode('utf8')
diff --git a/jupyterhub/apihandlers/base.py b/jupyterhub/apihandlers/base.py
index a63233b2..7b948abf 100644
--- a/jupyterhub/apihandlers/base.py
+++ b/jupyterhub/apihandlers/base.py
@@ -26,16 +26,16 @@ class APIHandler(BaseHandler):
         # If no header is provided, assume it comes from a script/curl.
         # We are only concerned with cross-site browser stuff here.
         if not host:
-            self.log.warn("Blocking API request with no host")
+            self.log.warning("Blocking API request with no host")
             return False
         if not referer:
-            self.log.warn("Blocking API request with no referer")
+            self.log.warning("Blocking API request with no referer")
             return False
         
         host_path = url_path_join(host, self.hub.server.base_url)
         referer_path = referer.split('://', 1)[-1]
         if not (referer_path + '/').startswith(host_path):
-            self.log.warn("Blocking Cross Origin API request.  Referer: %s, Host: %s",
+            self.log.warning("Blocking Cross Origin API request.  Referer: %s, Host: %s",
                 referer, host_path)
             return False
         return True
diff --git a/jupyterhub/apihandlers/users.py b/jupyterhub/apihandlers/users.py
index aa4488ae..b6fbd67c 100644
--- a/jupyterhub/apihandlers/users.py
+++ b/jupyterhub/apihandlers/users.py
@@ -41,7 +41,7 @@ class UserListAPIHandler(APIHandler):
                 continue
             user = self.find_user(name)
             if user is not None:
-                self.log.warn("User %s already exists" % name)
+                self.log.warning("User %s already exists" % name)
             else:
                 to_create.append(name)
         
@@ -195,7 +195,7 @@ class UserAdminAccessAPIHandler(APIHandler):
     @admin_only
     def post(self, name):
         current = self.get_current_user()
-        self.log.warn("Admin user %s has requested access to %s's server",
+        self.log.warning("Admin user %s has requested access to %s's server",
             current.name, name,
         )
         if not self.settings.get('admin_access', False):
diff --git a/jupyterhub/app.py b/jupyterhub/app.py
index b5eeb729..d6c0c767 100644
--- a/jupyterhub/app.py
+++ b/jupyterhub/app.py
@@ -293,7 +293,7 @@ class JupyterHub(Application):
     def _proxy_auth_token_default(self):
         token = os.environ.get('CONFIGPROXY_AUTH_TOKEN', None)
         if not token:
-            self.log.warn('\n'.join([
+            self.log.warning('\n'.join([
                 "",
                 "Generating CONFIGPROXY_AUTH_TOKEN. Restarting the Hub will require restarting the proxy.",
                 "Set CONFIGPROXY_AUTH_TOKEN env or JupyterHub.proxy_auth_token config to avoid this message.",
@@ -599,7 +599,7 @@ class JupyterHub(Application):
             try:
                 os.chmod(secret_file, 0o600)
             except OSError:
-                self.log.warn("Failed to set permissions on %s", secret_file)
+                self.log.warning("Failed to set permissions on %s", secret_file)
         # store the loaded trait value
         self.cookie_secret = secret
     
@@ -691,7 +691,7 @@ class JupyterHub(Application):
         db = self.db
         
         if self.admin_users and not self.authenticator.admin_users:
-            self.log.warn(
+            self.log.warning(
                 "\nJupyterHub.admin_users is deprecated."
                 "\nUse Authenticator.admin_users instead."
             )
@@ -776,7 +776,7 @@ class JupyterHub(Application):
         @gen.coroutine
         def user_stopped(user):
             status = yield user.spawner.poll()
-            self.log.warn("User %s server stopped with exit code: %s",
+            self.log.warning("User %s server stopped with exit code: %s",
                 user.name, status,
             )
             yield self.proxy.delete_user(user)
@@ -800,7 +800,7 @@ class JupyterHub(Application):
                 # user not running. This is expected if server is None,
                 # but indicates the user's server died while the Hub wasn't running
                 # if user.server is defined.
-                log = self.log.warn if user.server else self.log.debug
+                log = self.log.warning if user.server else self.log.debug
                 log("%s not running.", user.name)
                 user.server = None
 
@@ -998,7 +998,7 @@ class JupyterHub(Application):
         self.load_config_file(self.config_file)
         self.init_logging()
         if 'JupyterHubApp' in self.config:
-            self.log.warn("Use JupyterHub in config, not JupyterHubApp. Outdated config:\n%s",
+            self.log.warning("Use JupyterHub in config, not JupyterHubApp. Outdated config:\n%s",
                 '\n'.join('JupyterHubApp.{key} = {value!r}'.format(key=key, value=value)
                     for key, value in self.config.JupyterHubApp.items()
                 )
@@ -1098,7 +1098,7 @@ class JupyterHub(Application):
                 continue
             user = orm.User.find(self.db, route['user'])
             if user is None:
-                self.log.warn("Found no user for route: %s", route)
+                self.log.warning("Found no user for route: %s", route)
                 continue
             try:
                 dt = datetime.strptime(route['last_activity'], ISO8601_ms)
diff --git a/jupyterhub/auth.py b/jupyterhub/auth.py
index 08f4cd90..8ed982ee 100644
--- a/jupyterhub/auth.py
+++ b/jupyterhub/auth.py
@@ -383,9 +383,9 @@ class PAMAuthenticator(LocalAuthenticator):
             pamela.authenticate(username, data['password'], service=self.service)
         except pamela.PAMError as e:
             if handler is not None:
-                self.log.warn("PAM Authentication failed (%s@%s): %s", username, handler.request.remote_ip, e)
+                self.log.warning("PAM Authentication failed (%s@%s): %s", username, handler.request.remote_ip, e)
             else:
-                self.log.warn("PAM Authentication failed: %s", e)
+                self.log.warning("PAM Authentication failed: %s", e)
         else:
             return username
     
@@ -396,8 +396,8 @@ class PAMAuthenticator(LocalAuthenticator):
         try:
             pamela.open_session(user.name, service=self.service)
         except pamela.PAMError as e:
-            self.log.warn("Failed to open PAM session for %s: %s", user.name, e)
-            self.log.warn("Disabling PAM sessions from now on.")
+            self.log.warning("Failed to open PAM session for %s: %s", user.name, e)
+            self.log.warning("Disabling PAM sessions from now on.")
             self.open_sessions = False
     
     def post_spawn_stop(self, user, spawner):
@@ -407,7 +407,7 @@ class PAMAuthenticator(LocalAuthenticator):
         try:
             pamela.close_session(user.name, service=self.service)
         except pamela.PAMError as e:
-            self.log.warn("Failed to close PAM session for %s: %s", user.name, e)
-            self.log.warn("Disabling PAM sessions from now on.")
+            self.log.warning("Failed to close PAM session for %s: %s", user.name, e)
+            self.log.warning("Disabling PAM sessions from now on.")
             self.open_sessions = False
     
diff --git a/jupyterhub/handlers/base.py b/jupyterhub/handlers/base.py
index 96f6e2cb..fcf4902c 100644
--- a/jupyterhub/handlers/base.py
+++ b/jupyterhub/handlers/base.py
@@ -154,14 +154,14 @@ class BaseHandler(RequestHandler):
 
         if cookie_id is None:
             if self.get_cookie(cookie_name):
-                self.log.warn("Invalid or expired cookie token")
+                self.log.warning("Invalid or expired cookie token")
                 clear()
             return
         cookie_id = cookie_id.decode('utf8', 'replace')
         u = self.db.query(orm.User).filter(orm.User.cookie_id==cookie_id).first()
         user = self._user_from_orm(u)
         if user is None:
-            self.log.warn("Invalid cookie token")
+            self.log.warning("Invalid cookie token")
             # have cookie, but it's not valid. Clear it and start over.
             clear()
         return user
@@ -309,7 +309,7 @@ class BaseHandler(RequestHandler):
             if user.spawn_pending:
                 # still in Spawner.start, which is taking a long time
                 # we shouldn't poll while spawn_pending is True
-                self.log.warn("User %s server is slow to start", user.name)
+                self.log.warning("User %s server is slow to start", user.name)
                 # schedule finish for when the user finishes spawning
                 IOLoop.current().add_future(f, finish_user_spawn)
             else:
@@ -319,7 +319,7 @@ class BaseHandler(RequestHandler):
                 if status is None:
                     # hit timeout, but server's running. Hope that it'll show up soon enough,
                     # though it's possible that it started at the wrong URL
-                    self.log.warn("User %s server is slow to become responsive", user.name)
+                    self.log.warning("User %s server is slow to become responsive", user.name)
                     # schedule finish for when the user finishes spawning
                     IOLoop.current().add_future(f, finish_user_spawn)
                 else:
@@ -333,7 +333,7 @@ class BaseHandler(RequestHandler):
         status = yield user.spawner.poll()
         if status is None:
             status = 'unknown'
-        self.log.warn("User %s server stopped, with exit code: %s",
+        self.log.warning("User %s server stopped, with exit code: %s",
             user.name, status,
         )
         yield self.proxy.delete_user(user)
@@ -364,7 +364,7 @@ class BaseHandler(RequestHandler):
         except gen.TimeoutError:
             if user.stop_pending:
                 # hit timeout, but stop is still pending
-                self.log.warn("User %s server is slow to stop", user.name)
+                self.log.warning("User %s server is slow to stop", user.name)
                 # schedule finish for when the server finishes stopping
                 IOLoop.current().add_future(f, finish_stop)
             else:
@@ -509,7 +509,7 @@ class CSPReportHandler(BaseHandler):
     @web.authenticated
     def post(self):
         '''Log a content security policy violation report'''
-        self.log.warn("Content security violation: %s",
+        self.log.warning("Content security violation: %s",
                       self.request.body.decode('utf8', 'replace'))
 
 default_handlers = [
diff --git a/jupyterhub/handlers/pages.py b/jupyterhub/handlers/pages.py
index 8860b860..3879c1c3 100644
--- a/jupyterhub/handlers/pages.py
+++ b/jupyterhub/handlers/pages.py
@@ -123,10 +123,10 @@ class AdminHandler(BaseHandler):
         orders = self.get_arguments('order')
 
         for bad in set(sorts).difference(available):
-            self.log.warn("ignoring invalid sort: %r", bad)
+            self.log.warning("ignoring invalid sort: %r", bad)
             sorts.remove(bad)
         for bad in set(orders).difference({'asc', 'desc'}):
-            self.log.warn("ignoring invalid order: %r", bad)
+            self.log.warning("ignoring invalid order: %r", bad)
             orders.remove(bad)
 
         # add default sort as secondary
diff --git a/jupyterhub/spawner.py b/jupyterhub/spawner.py
index 68badf11..e0e66fff 100644
--- a/jupyterhub/spawner.py
+++ b/jupyterhub/spawner.py
@@ -528,5 +528,5 @@ class LocalProcessSpawner(Spawner):
         status = yield self.poll()
         if status is None:
             # it all failed, zombie process
-            self.log.warn("Process %i never died", self.pid)
+            self.log.warning("Process %i never died", self.pid)
     
diff --git a/jupyterhub/user.py b/jupyterhub/user.py
index fdadaabc..c1e5dae9 100644
--- a/jupyterhub/user.py
+++ b/jupyterhub/user.py
@@ -228,7 +228,7 @@ class User(HasTraits):
             yield gen.with_timeout(timedelta(seconds=spawner.start_timeout), f)
         except Exception as e:
             if isinstance(e, gen.TimeoutError):
-                self.log.warn("{user}'s server failed to start in {s} seconds, giving up".format(
+                self.log.warning("{user}'s server failed to start in {s} seconds, giving up".format(
                     user=self.name, s=spawner.start_timeout,
                 ))
                 e.reason = 'timeout'
@@ -256,7 +256,7 @@ class User(HasTraits):
             yield self.server.wait_up(http=True, timeout=spawner.http_timeout)
         except Exception as e:
             if isinstance(e, TimeoutError):
-                self.log.warn(
+                self.log.warning(
                     "{user}'s server never showed up at {url} "
                     "after {http_timeout} seconds. Giving up".format(
                         user=self.name,
diff --git a/jupyterhub/utils.py b/jupyterhub/utils.py
index 75e046e0..29d36495 100644
--- a/jupyterhub/utils.py
+++ b/jupyterhub/utils.py
@@ -78,14 +78,14 @@ def wait_for_http_server(url, timeout=10):
                 if e.code != 599:
                     # we expect 599 for no connection,
                     # but 502 or other proxy error is conceivable
-                    app_log.warn("Server at %s responded with error: %s", url, e.code)
+                    app_log.warning("Server at %s responded with error: %s", url, e.code)
                 yield gen.sleep(0.1)
             else:
                 app_log.debug("Server at %s responded with %s", url, e.code)
                 return
         except (OSError, socket.error) as e:
             if e.errno not in {errno.ECONNABORTED, errno.ECONNREFUSED, errno.ECONNRESET}:
-                app_log.warn("Failed to connect to %s (%s)", url, e)
+                app_log.warning("Failed to connect to %s (%s)", url, e)
             yield gen.sleep(0.1)
         else:
             return