diff --git a/README.md b/README.md
index d5e0c97..d09dc2e 100644
--- a/README.md
+++ b/README.md
@@ -66,6 +66,8 @@ cdm.parse_license(session_id, response.text)
 
 for key in cdm.get_keys(session_id):
     print(f"{key.key_id.hex}:{key.key.hex()}")
+
+cdm.close(session_id)
 ```
 
 ## Disclaimer
diff --git a/pyplayready/cdm.py b/pyplayready/cdm.py
index 2d385ba..df907e9 100644
--- a/pyplayready/cdm.py
+++ b/pyplayready/cdm.py
@@ -3,7 +3,7 @@ from __future__ import annotations
 import base64
 import math
 import time
-from typing import List
+from typing import List, Union
 from uuid import UUID
 import xml.etree.ElementTree as ET
 
@@ -32,9 +32,9 @@ class Cdm:
     def __init__(
             self,
             security_level: int,
-            certificate_chain: CertificateChain,
-            encryption_key: ECCKey,
-            signing_key: ECCKey,
+            certificate_chain: Union[CertificateChain, None],
+            encryption_key: Union[ECCKey, None],
+            signing_key: Union[ECCKey, None],
             client_version: str = "10.0.16384.10011",
             protocol_version: int = 1
     ):
diff --git a/pyplayready/main.py b/pyplayready/main.py
index 83eca9c..9cfff2b 100644
--- a/pyplayready/main.py
+++ b/pyplayready/main.py
@@ -52,6 +52,9 @@ def license_(device_path: Path, pssh: PSSH, server: str) -> None:
     cdm = Cdm.from_device(device)
     log.info("Loaded CDM")
 
+    session_id = cdm.open()
+    log.info("Opened Session")
+
     challenge = cdm.get_license_challenge(pssh.get_wrm_headers(downgrade_to_v4=True)[0])
     log.info("Created License Request (Challenge)")
     log.debug(challenge)
@@ -78,6 +81,9 @@ def license_(device_path: Path, pssh: PSSH, server: str) -> None:
     for key in cdm.get_keys():
         log.info(f"{key.key_id.hex}:{key.key.hex()}")
 
+    cdm.close(session_id)
+    log.info("Clossed Session")
+
 
 @main.command()
 @click.argument("device", type=Path)
@@ -232,7 +238,7 @@ def export_device(ctx: click.Context, prd_path: Path, out_dir: Optional[Path] =
 @main.command("serve", short_help="Serve your local CDM and Playready Devices Remotely.")
 @click.argument("config_path", type=Path)
 @click.option("-h", "--host", type=str, default="127.0.0.1", help="Host to serve from.")
-@click.option("-p", "--port", type=int, default=8786, help="Port to serve from.")
+@click.option("-p", "--port", type=int, default=7723, help="Port to serve from.")
 def serve_(config_path: Path, host: str, port: int) -> None:
     """
     Serve your local CDM and Playready Devices Remotely.
diff --git a/pyplayready/remotecdm.py b/pyplayready/remotecdm.py
index 2d778ff..317e131 100644
--- a/pyplayready/remotecdm.py
+++ b/pyplayready/remotecdm.py
@@ -5,9 +5,7 @@ import re
 import requests
 
 from pyplayready.cdm import Cdm
-from pyplayready.bcert import CertificateChain
 from pyplayready.device import Device
-from pyplayready.ecc_key import ECCKey
 from pyplayready.key import Key
 
 from pyplayready.exceptions import (DeviceMismatch, InvalidInitData)
@@ -49,7 +47,7 @@ class RemoteCdm(Cdm):
         self.device_name = device_name
 
         # spoof certificate_chain and ecc_key just so we can construct via super call
-        super().__init__(security_level, CertificateChain, ECCKey, ECCKey)
+        super().__init__(security_level, None, None, None)
 
         self.__session = requests.Session()
         self.__session.headers.update({
@@ -97,20 +95,18 @@ class RemoteCdm(Cdm):
     def get_license_challenge(
         self,
         session_id: bytes,
-        pssh: str,
-        downgrade: str
+        wrm_header: str,
     ) -> str:
-        if not pssh:
-            raise InvalidInitData("A pssh must be provided.")
-        if not isinstance(pssh, str):
-            raise InvalidInitData(f"Expected pssh to be a {str}, not {pssh!r}")
+        if not wrm_header:
+            raise InvalidInitData("A wrm_header must be provided.")
+        if not isinstance(wrm_header, str):
+            raise InvalidInitData(f"Expected wrm_header to be a {str}, not {wrm_header!r}")
 
         r = self.__session.post(
             url=f"{self.host}/{self.device_name}/get_license_challenge",
             json={
                 "session_id": session_id.hex(),
-                "init_data": pssh,
-                "downgrade": downgrade,
+                "init_data": wrm_header,
             }
         ).json()
         if r["status"] != 200:
diff --git a/pyplayready/serve.py b/pyplayready/serve.py
index 60d9bda..175a91c 100644
--- a/pyplayready/serve.py
+++ b/pyplayready/serve.py
@@ -115,7 +115,7 @@ async def get_license_challenge(request: web.Request) -> web.Response:
     device_name = request.match_info["device"]
 
     body = await request.json()
-    for required_field in ("session_id", "init_data", "downgrade"):
+    for required_field in ("session_id", "init_data"):
         if not body.get(required_field):
             return web.json_response({
                 "status": 400,
@@ -125,11 +125,6 @@ async def get_license_challenge(request: web.Request) -> web.Response:
     # get session id
     session_id = bytes.fromhex(body["session_id"])
 
-    # get downgrade
-    downgrade = False
-    if body['downgrade'] == 'true':
-        downgrade = True
-
     # get cdm
     cdm: Optional[Cdm] = request.app["cdms"].get((secret_key, device_name))
     if not cdm:
@@ -139,13 +134,14 @@ async def get_license_challenge(request: web.Request) -> web.Response:
         }, status=400)
 
     # get init data
-    init_data = PSSH(body["init_data"]).get_wrm_headers(downgrade_to_v4=downgrade)
+    # init_data = PSSH(body["init_data"]).get_wrm_headers(downgrade_to_v4=downgrade)
+    init_data = body["init_data"]
 
     # get challenge
     try:
         license_request = cdm.get_license_challenge(
             session_id=session_id,
-            content_header=init_data[0],
+            content_header=init_data,
         )
     except InvalidSession:
         return web.json_response({