diff --git a/ocpp/charge_point.py b/ocpp/charge_point.py
index 7046cada5..601871488 100644
--- a/ocpp/charge_point.py
+++ b/ocpp/charge_point.py
@@ -25,8 +25,7 @@ def camel_to_snake_case(data):
     if isinstance(data, dict):
         snake_case_dict = {}
         for key, value in data.items():
-            key = key.replace("ocppCSMS", "ocpp_csms")
-            key = key.replace("V2X", "_v2x")
+            key = key.replace("ocppCSMSURL", "ocpp_csms_url")
             key = key.replace("V2X", "_v2x").replace("V2G", "_v2g")
             s1 = re.sub("(.)([A-Z][a-z]+)", r"\1_\2", key)
             key = re.sub("([a-z0-9])([A-Z])(?=\\S)", r"\1_\2", s1).lower()
@@ -57,7 +56,10 @@ def snake_to_camel_case(data):
         for key, value in data.items():
             key = key.replace("soc", "SoC")
             key = key.replace("_v2x", "V2X")
-            key = key.replace("ocpp_csms", "ocppCSMS")
+            # The spec uses inconsent casing for "csms" and "url".
+            # E.g. "OcppCsmsUrl" vs "ResponderURL" and "CSMSRootCertificate"
+            key = key.replace("ocpp_csms_url", "ocppCsmsUrl")
+            key = key.replace("csms", "CSMS")
             key = key.replace("_url", "URL")
             key = key.replace("soc", "SoC").replace("_SoCket", "Socket")
             key = key.replace("_v2x", "V2X")
diff --git a/tests/test_charge_point.py b/tests/test_charge_point.py
index b1ab1412b..00571f9fd 100644
--- a/tests/test_charge_point.py
+++ b/tests/test_charge_point.py
@@ -68,6 +68,7 @@ def heartbeat(self, **kwargs):
         ({"responderURL": "foo.com"}, {"responder_url": "foo.com"}),
         ({"url": "foo.com"}, {"url": "foo.com"}),
         ({"ocppCSMSURL": "foo.com"}, {"ocpp_csms_url": "foo.com"}),
+        ({"CSMSRootCertificate": "foo.com"}, {"csms_root_certificate": "foo.com"}),
         ({"InvalidURL": "foo.com"}, {"invalid_url": "foo.com"}),
         ({"evMinV2XEnergyRequest": 200}, {"ev_min_v2x_energy_request": 200}),
         ({"v2xChargingCtrlr": 200}, {"v2x_charging_ctrlr": 200}),
@@ -94,7 +95,8 @@ def test_camel_to_snake_case(test_input, expected):
         ({"v2x_charging_ctrlr": 200}, {"v2xChargingCtrlr": 200}),
         ({"responder_url": "foo.com"}, {"responderURL": "foo.com"}),
         ({"url": "foo.com"}, {"url": "foo.com"}),
-        ({"ocpp_csms_url": "foo.com"}, {"ocppCSMSURL": "foo.com"}),
+        ({"ocpp_csms_url": "foo.com"}, {"ocppCsmsUrl": "foo.com"}),
+        ({"csms_root_certificate": "foo.com"}, {"CSMSRootCertificate": "foo.com"}),
         ({"invalid_url": "foo.com"}, {"invalidURL": "foo.com"}),
         ({"web_socket_ping_interval": 200}, {"webSocketPingInterval": 200}),
         ({"sign_v2g_certificate": 200}, {"signV2GCertificate": 200}),