diff --git a/custom/4.0.0/requirements.txt b/custom/4.0.0/requirements.txt
index cd22d48c74cfd8237f594a38d1830643d9a5966b..d9d894cd15f3d6c4d58ff24305b567e87bbe0571 100644
--- a/custom/4.0.0/requirements.txt
+++ b/custom/4.0.0/requirements.txt
@@ -1,4 +1,4 @@
 jsonformatter==0.3.1
-jupyterhub-backendspawner==0.3.3
+jupyterhub-backendspawner==0.4.0
 oauthenticator==14.2.0
 # nodeenv==1.6.0
diff --git a/custom/4.0.0/spawner/api_setup_tunnel.py b/custom/4.0.0/spawner/api_setup_tunnel.py
index c09465edcebe0167a1d4eb4ba62fdc297d89b250..ba29dba62acc0bc445aee8a6b9907ae6dbe90594 100644
--- a/custom/4.0.0/spawner/api_setup_tunnel.py
+++ b/custom/4.0.0/spawner/api_setup_tunnel.py
@@ -63,7 +63,7 @@ class SetupTunnelAPIHandler(APIHandler):
             )
 
             json_body["servername"] = spawner.name
-            json_body["svc_port"] = await spawner.get_port()
+            json_body["svc_port"] = spawner.port
             json_body["svc_name"] = spawner.get_service_address().split(".")[0]
             labels = {
                 "hub.jupyter.org/username": user.name,