diff --git a/duo_universal/client.py b/duo_universal/client.py
index c6f6f42..c6241d7 100644
--- a/duo_universal/client.py
+++ b/duo_universal/client.py
@@ -45,6 +45,7 @@
 OAUTH_V1_AUTHORIZE_ENDPOINT = "https://{}/oauth/v1/authorize"
 OAUTH_V1_TOKEN_ENDPOINT = "https://{}/oauth/v1/token"
 DEFAULT_CA_CERT_PATH = os.path.join(os.path.dirname(__file__), 'ca_certs.pem')
+CA_BUNDLE_VERSION = "1.0"
 
 CLIENT_ASSERT_TYPE = "urn:ietf:params:oauth:client-assertion-type:jwt-bearer"
 
@@ -316,10 +317,15 @@ def exchange_authorization_code_for_2fa_result(self, duoCode, username, nonce=No
                                            algorithm='HS512')
         }
         try:
+            ca_pinning_status = "disabled" if self._disable_ca_pinning else "enabled"
             user_agent = ("duo_universal_python/{version} "
-                          "python/{python_version} {os_name}").format(version=__version__,
-                                                                      python_version=platform.python_version(),
-                                                                      os_name=platform.platform())
+                          "python/{python_version} {os_name} "
+                          "ca_bundle/{ca_bundle_version} "
+                          "(ca_pinning={ca_pinning_status})").format(version=__version__,
+                                                                     python_version=platform.python_version(),
+                                                                     os_name=platform.platform(),
+                                                                     ca_bundle_version=CA_BUNDLE_VERSION,
+                                                                     ca_pinning_status=ca_pinning_status)
             response = requests.post(token_endpoint,
                                      params=all_args,
                                      headers={"user-agent":
diff --git a/tests/test_setup_client.py b/tests/test_setup_client.py
index 03dd04f..296fc3a 100644
--- a/tests/test_setup_client.py
+++ b/tests/test_setup_client.py
@@ -253,5 +253,51 @@ def test_token_exchange_pinning_enabled_uses_bundled_certs(self, requests_mock):
         self.assertEqual(kwargs['verify'], client.DEFAULT_CA_CERT_PATH)
 
 
+class TestUserAgent(unittest.TestCase):
+
+    @patch('requests.post')
+    def test_user_agent_includes_ca_bundle_version(self, requests_mock):
+        mock_response = MagicMock()
+        mock_response.status_code = 200
+        mock_response.json.return_value = {'id_token': 'fake'}
+        requests_mock.return_value = mock_response
+        c = client.Client(CLIENT_ID, CLIENT_SECRET, HOST, REDIRECT_URI)
+        try:
+            c.exchange_authorization_code_for_2fa_result('code', 'user')
+        except client.DuoException:
+            pass
+        _, kwargs = requests_mock.call_args
+        self.assertIn('ca_bundle/1.0', kwargs['headers']['user-agent'])
+
+    @patch('requests.post')
+    def test_user_agent_ca_pinning_enabled(self, requests_mock):
+        mock_response = MagicMock()
+        mock_response.status_code = 200
+        mock_response.json.return_value = {'id_token': 'fake'}
+        requests_mock.return_value = mock_response
+        c = client.Client(CLIENT_ID, CLIENT_SECRET, HOST, REDIRECT_URI)
+        try:
+            c.exchange_authorization_code_for_2fa_result('code', 'user')
+        except client.DuoException:
+            pass
+        _, kwargs = requests_mock.call_args
+        self.assertIn('(ca_pinning=enabled)', kwargs['headers']['user-agent'])
+
+    @patch('requests.post')
+    def test_user_agent_ca_pinning_disabled(self, requests_mock):
+        mock_response = MagicMock()
+        mock_response.status_code = 200
+        mock_response.json.return_value = {'id_token': 'fake'}
+        requests_mock.return_value = mock_response
+        c = client.Client(CLIENT_ID, CLIENT_SECRET, HOST, REDIRECT_URI,
+                          disable_ca_pinning=True)
+        try:
+            c.exchange_authorization_code_for_2fa_result('code', 'user')
+        except client.DuoException:
+            pass
+        _, kwargs = requests_mock.call_args
+        self.assertIn('(ca_pinning=disabled)', kwargs['headers']['user-agent'])
+
+
 if __name__ == '__main__':
     unittest.main()