diff --git a/main.py b/main.py
index 13fe739..a0e29ce 100755
--- a/main.py
+++ b/main.py
@@ -1,8 +1,10 @@
 import os
+import sys
 import time
 import ujson
 import machine
 import network
+import ssl
 from umqtt.simple import MQTTClient
 
 #Enter your wifi SSID and password below.
@@ -15,22 +17,21 @@
 aws_endpoint = b'AWS_ENDPOINT.amazonaws.com'
 
 #If you followed the blog, these names are already set.
+# To validate the IoT endpoint, the Amazon Root CA cert is needed.
+# You can get this from https://www.amazontrust.com/repository/AmazonRootCA1.pem
+# This can also be downloaded when creating the certs for your device in the IoT Console
+# For more details:
+#   https://docs.aws.amazon.com/iot/latest/developerguide/server-authentication.html#server-authentication-certs
 thing_name = "BlogThing"
 client_id = "BlogClient"
 private_key = "private.pem.key"
 private_cert = "cert.pem.crt"
-
-#Read the files used to authenticate to AWS IoT Core
-with open(private_key, 'r') as f:
-    key = f.read()
-with open(private_cert, 'r') as f:
-    cert = f.read()
+ca_cert = "AmazonRootCA1.pem"
 
 #These are the topics we will subscribe to. We will publish updates to /update.
 #We will subscribe to the /update/delta topic to look for changes in the device shadow.
 topic_pub = "$aws/things/" + thing_name + "/shadow/update"
 topic_sub = "$aws/things/" + thing_name + "/shadow/update/delta"
-ssl_params = {"key":key, "cert":cert, "server_side":False}
 
 #Define pins for LED and light sensor. In this example we are using a FeatherS2.
 #The sensor and LED are built into the board, and no external connections are required.
@@ -51,12 +52,37 @@
     print('Connection successful')
     print('Network config:', wlan.ifconfig())
 
-def mqtt_connect(client=client_id, endpoint=aws_endpoint, sslp=ssl_params):
-    mqtt = MQTTClient(client_id=client, server=endpoint, port=8883, keepalive=1200, ssl=True, ssl_params=sslp)
+def connect_to_iot(mqtt_client):
     print("Connecting to AWS IoT...")
-    mqtt.connect()
+    mqtt_client.connect()
     print("Done")
-    return mqtt
+    return mqtt_client
+
+# used for micropython 1.23 and above
+def mqtt_connect_new(client=client_id, endpoint=aws_endpoint, key=private_key, cert=private_cert, ca=ca_cert):
+    ctx = ssl.SSLContext(ssl.PROTOCOL_TLS_CLIENT)
+
+    # cert and key must be strings if using a file path.
+    # If these are bytes (b""), then they are interpreted as the cert data
+    ctx.load_cert_chain(cert, key)
+
+    # to verify the IoT Endpoint's certificate is valid
+    ctx.load_verify_locations(cafile=ca)
+    ctx.verify_mode = ssl.CERT_REQUIRED
+
+    mqtt = MQTTClient(client_id=client, server=endpoint, port=8883, keepalive=1200, ssl=ctx)
+    return connect_to_iot(mqtt)
+
+# used for micropython 1.22 and below
+def mqtt_connect(client=client_id, endpoint=aws_endpoint):
+    with open(private_key, 'r') as f:
+        key = f.read()
+    with open(private_cert, 'r') as f:
+        cert = f.read()
+
+    sslp = {"key": key, "cert": cert, "server_side": False}
+    mqtt = MQTTClient(client_id=client, server=endpoint, port=8883, keepalive=1200, ssl=True, ssl_params=sslp)
+    return connect_to_iot(mqtt)
 
 def mqtt_publish(client, topic=topic_pub, message=''):
     print("Publishing message...")
@@ -74,6 +100,14 @@ def mqtt_subscribe(topic, msg):
 def led_state(message):
     led.value(message['state']['led']['onboard'])
 
+# determine micropython version
+# change the connection implementation if 1.23+ due to a breaking change with ssl
+# see: https://github.com/micropython/micropython-lib/pull/793
+if sys.implementation.version[1] >= 23:
+    mqtt_connect = mqtt_connect_new
+else:
+    mqtt_connect = mqtt_connect
+
 #We use our helper function to connect to AWS IoT Core.
 #The callback function mqtt_subscribe is what will be called if we 
 #get a new message on topic_sub.