diff --git a/homeassistant/components/plex/config_flow.py b/homeassistant/components/plex/config_flow.py
index a11fb9119a6..c03b958b2da 100644
--- a/homeassistant/components/plex/config_flow.py
+++ b/homeassistant/components/plex/config_flow.py
@@ -19,6 +19,7 @@ from homeassistant.util.json import load_json
 from .const import (  # pylint: disable=unused-import
     AUTH_CALLBACK_NAME,
     AUTH_CALLBACK_PATH,
+    CONF_CLIENT_IDENTIFIER,
     CONF_SERVER,
     CONF_SERVER_IDENTIFIER,
     CONF_USE_EPISODE_ART,
@@ -65,6 +66,7 @@ class PlexFlowHandler(config_entries.ConfigFlow, domain=DOMAIN):
         self.available_servers = None
         self.plexauth = None
         self.token = None
+        self.client_id = None
 
     async def async_step_user(self, user_input=None):
         """Handle a flow initialized by the user."""
@@ -116,6 +118,8 @@ class PlexFlowHandler(config_entries.ConfigFlow, domain=DOMAIN):
         token = server_config.get(CONF_TOKEN)
 
         entry_config = {CONF_URL: url}
+        if self.client_id:
+            entry_config[CONF_CLIENT_IDENTIFIER] = self.client_id
         if token:
             entry_config[CONF_TOKEN] = token
         if url.startswith("https"):
@@ -216,6 +220,7 @@ class PlexFlowHandler(config_entries.ConfigFlow, domain=DOMAIN):
             return self.async_external_step_done(next_step_id="timed_out")
 
         self.token = token
+        self.client_id = self.plexauth.client_identifier
         return self.async_external_step_done(next_step_id="use_external_token")
 
     async def async_step_timed_out(self, user_input=None):
diff --git a/homeassistant/components/plex/const.py b/homeassistant/components/plex/const.py
index d3a3a866361..0d512101e11 100644
--- a/homeassistant/components/plex/const.py
+++ b/homeassistant/components/plex/const.py
@@ -21,6 +21,7 @@ PLEX_NEW_MP_SIGNAL = "plex_new_mp_signal.{}"
 PLEX_UPDATE_MEDIA_PLAYER_SIGNAL = "plex_update_mp_signal.{}"
 PLEX_UPDATE_SENSOR_SIGNAL = "plex_update_sensor_signal.{}"
 
+CONF_CLIENT_IDENTIFIER = "client_id"
 CONF_SERVER = "server"
 CONF_SERVER_IDENTIFIER = "server_id"
 CONF_USE_EPISODE_ART = "use_episode_art"
diff --git a/homeassistant/components/plex/manifest.json b/homeassistant/components/plex/manifest.json
index d4f2ae0517a..3c570a0e64c 100644
--- a/homeassistant/components/plex/manifest.json
+++ b/homeassistant/components/plex/manifest.json
@@ -5,7 +5,7 @@
   "documentation": "https://www.home-assistant.io/integrations/plex",
   "requirements": [
     "plexapi==3.0.6",
-    "plexauth==0.0.4"
+    "plexauth==0.0.5"
   ],
   "dependencies": [
     "http"
diff --git a/homeassistant/components/plex/server.py b/homeassistant/components/plex/server.py
index d7825ae82c3..c0461ee0f54 100644
--- a/homeassistant/components/plex/server.py
+++ b/homeassistant/components/plex/server.py
@@ -12,6 +12,7 @@ from homeassistant.const import CONF_TOKEN, CONF_URL, CONF_VERIFY_SSL
 from homeassistant.helpers.dispatcher import dispatcher_send
 
 from .const import (
+    CONF_CLIENT_IDENTIFIER,
     CONF_SERVER,
     CONF_SHOW_ALL_CONTROLS,
     CONF_USE_EPISODE_ART,
@@ -33,8 +34,6 @@ plexapi.X_PLEX_DEVICE_NAME = X_PLEX_DEVICE_NAME
 plexapi.X_PLEX_PLATFORM = X_PLEX_PLATFORM
 plexapi.X_PLEX_PRODUCT = X_PLEX_PRODUCT
 plexapi.X_PLEX_VERSION = X_PLEX_VERSION
-plexapi.myplex.BASE_HEADERS = plexapi.reset_base_headers()
-plexapi.server.BASE_HEADERS = plexapi.reset_base_headers()
 
 
 class PlexServer:
@@ -52,6 +51,12 @@ class PlexServer:
         self.options = options
         self.server_choice = None
 
+        # Header conditionally added as it is not available in config entry v1
+        if CONF_CLIENT_IDENTIFIER in server_config:
+            plexapi.X_PLEX_IDENTIFIER = server_config[CONF_CLIENT_IDENTIFIER]
+        plexapi.myplex.BASE_HEADERS = plexapi.reset_base_headers()
+        plexapi.server.BASE_HEADERS = plexapi.reset_base_headers()
+
     def connect(self):
         """Connect to a Plex server directly, obtaining direct URL if necessary."""
 
diff --git a/requirements_all.txt b/requirements_all.txt
index 868855ed851..207b955f249 100644
--- a/requirements_all.txt
+++ b/requirements_all.txt
@@ -971,7 +971,7 @@ pizzapi==0.0.3
 plexapi==3.0.6
 
 # homeassistant.components.plex
-plexauth==0.0.4
+plexauth==0.0.5
 
 # homeassistant.components.plum_lightpad
 plumlightpad==0.0.11
diff --git a/requirements_test_all.txt b/requirements_test_all.txt
index 2fd91e21d96..e61732e632b 100644
--- a/requirements_test_all.txt
+++ b/requirements_test_all.txt
@@ -343,7 +343,7 @@ pillow==6.2.0
 plexapi==3.0.6
 
 # homeassistant.components.plex
-plexauth==0.0.4
+plexauth==0.0.5
 
 # homeassistant.components.mhz19
 # homeassistant.components.serial_pm