diff --git a/apache-kafka-2/src/main/java/com/baeldung/kafka/message/ordering/ProducerConfigurations.java b/apache-kafka-2/src/main/java/com/baeldung/kafka/message/ordering/ProducerConfigurations.java
index 5dc917e308..af06fa04de 100644
--- a/apache-kafka-2/src/main/java/com/baeldung/kafka/message/ordering/ProducerConfigurations.java
+++ b/apache-kafka-2/src/main/java/com/baeldung/kafka/message/ordering/ProducerConfigurations.java
@@ -10,7 +10,7 @@ public class ProducerConfigurations {
     public static void main(String[] args) {
         Properties props = new Properties();
         props.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, "localhost:9092");
-        props.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer");
+        props.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, "org.apache.kafka.common.serialization.StringSerializer");
         props.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, "org.apache.kafka.common.serialization.StringSerializer");
         props.put(ProducerConfig.MAX_IN_FLIGHT_REQUESTS_PER_CONNECTION, "1");
         props.put(ProducerConfig.BATCH_SIZE_CONFIG, "16384");