diff --git a/hc2mqtt.py b/hc2mqtt.py
index dbee2de..6b68d48 100755
--- a/hc2mqtt.py
+++ b/hc2mqtt.py
@@ -179,7 +179,7 @@ def client_connect(client, device, mqtt_topic):
 
             while True:
                 msg = dev[device["name"]].recv()
-                client.publish(F"{mqtt_topic}/LWT", "online")
+                client.publish(f"{mqtt_topic}/LWT", "online")
                 if msg is None:
                     break
                 if len(msg) > 0:
@@ -211,7 +211,7 @@ def client_connect(client, device, mqtt_topic):
 
         except Exception as e:
             print(now(), device["name"], "ERROR", e, file=sys.stderr)
-            client.publish(F"{mqtt_topic}/LWT", "offline", retain=True)
+            client.publish(f"{mqtt_topic}/LWT", "offline", retain=True)
 
         time.sleep(40)