diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4f8807e63..8b66b4ae3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,7 +3,7 @@
 ## Commits to `main`
 
 ### Changes
- - Add more checks for malformed packets when deserializing acknowledgments.
+ - [#159](https://github.com/FreeRTOS/coreMQTT/pull/159) Add more checks for malformed packets when deserializing acknowledgments.
 
 ## v1.1.1 (February 2021)
 
diff --git a/source/core_mqtt_serializer.c b/source/core_mqtt_serializer.c
index 7e8e30b45..ea466d00a 100644
--- a/source/core_mqtt_serializer.c
+++ b/source/core_mqtt_serializer.c
@@ -24,11 +24,9 @@
  * @file core_mqtt_serializer.c
  * @brief Implements the user-facing functions in core_mqtt_serializer.h.
  */
-#include <cstdint>
 #include <string.h>
 #include <assert.h>
 
-#include "core_mqtt.h"
 #include "core_mqtt_serializer.h"
 
 /**
@@ -1166,7 +1164,7 @@ static MQTTStatus_t deserializeSuback( const MQTTPacketInfo_t * pSuback,
         LogDebug( ( "Packet identifier %hu.",
                     ( unsigned short ) *pPacketIdentifier ) );
 
-        if( *pPacketIdentifier == MQTT_PACKET_ID_INVALID )
+        if( *pPacketIdentifier == 0U )
         {
             status = MQTTBadResponse;
         }