diff --git a/pom.xml b/pom.xml
index 8f13be12..5fcf37d5 100644
--- a/pom.xml
+++ b/pom.xml
@@ -118,8 +118,8 @@
         </dependency>
         <dependency>
             <groupId>software.amazon.lambda</groupId>
-            <artifactId>powertools-logging</artifactId>
-            <version>1.20.2</version>
+            <artifactId>powertools-logging-logback</artifactId>
+            <version>2.1.1</version>
         </dependency>
         <dependency>
             <groupId>org.aspectj</groupId>
diff --git a/src/main/java/software/nhs/fhirvalidator/configuration/ValidatorConfiguration.java b/src/main/java/software/nhs/fhirvalidator/configuration/ValidatorConfiguration.java
index 3b9e39fb..6b64947f 100644
--- a/src/main/java/software/nhs/fhirvalidator/configuration/ValidatorConfiguration.java
+++ b/src/main/java/software/nhs/fhirvalidator/configuration/ValidatorConfiguration.java
@@ -31,8 +31,8 @@
 import software.nhs.fhirvalidator.models.SimplifierPackage;
 import software.nhs.fhirvalidator.util.ResourceUtils;
 
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * This class is a wrapper around the HAPI FhirValidator.
@@ -46,7 +46,7 @@ public class ValidatorConfiguration {
     public final FhirContext fhirContext;
     public final List<NpmPackage> npmPackages = new ArrayList<>();
 
-    Logger log = LogManager.getLogger(ValidatorConfiguration.class);
+    Logger log = LoggerFactory.getLogger(ValidatorConfiguration.class);
 
     public ValidatorConfiguration(String _PROFILE_MANIFEST_FILE) {
         PROFILE_MANIFEST_FILE = _PROFILE_MANIFEST_FILE;
diff --git a/src/main/java/software/nhs/fhirvalidator/controller/ValidateController.java b/src/main/java/software/nhs/fhirvalidator/controller/ValidateController.java
index 9fdfa4b6..df4a7a4d 100644
--- a/src/main/java/software/nhs/fhirvalidator/controller/ValidateController.java
+++ b/src/main/java/software/nhs/fhirvalidator/controller/ValidateController.java
@@ -23,8 +23,8 @@
 import software.nhs.fhirvalidator.service.MessageDefinitionApplier;
 import software.nhs.fhirvalidator.util.OperationOutcomeUtils;
 
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * This class is a wrapper around the HAPI FhirValidator.
@@ -40,7 +40,7 @@ public class ValidateController {
     private CapabilityStatementApplier capabilityStatementApplier;
     private MessageDefinitionApplier messageDefinitionApplier;
 
-    Logger log = LogManager.getLogger(ValidateController.class);
+    Logger log = LoggerFactory.getLogger(ValidateController.class);
 
     public ValidateController(String PROFILE_MANIFEST_FILE) {
         validatorConfiguration = new ValidatorConfiguration(PROFILE_MANIFEST_FILE);
diff --git a/src/main/java/software/nhs/fhirvalidator/handler/HandlerStream.java b/src/main/java/software/nhs/fhirvalidator/handler/HandlerStream.java
index 3fe331c5..e79e7a26 100644
--- a/src/main/java/software/nhs/fhirvalidator/handler/HandlerStream.java
+++ b/src/main/java/software/nhs/fhirvalidator/handler/HandlerStream.java
@@ -11,18 +11,18 @@
 import com.google.gson.JsonObject;
 import com.google.gson.JsonParser;
 
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.slf4j.MDC;
 
 import software.amazon.lambda.powertools.logging.Logging;
-import software.amazon.lambda.powertools.logging.LoggingUtils;
 import software.nhs.fhirvalidator.controller.ValidateController;
 import software.nhs.fhirvalidator.util.ResourceUtils;
 
 public class HandlerStream implements RequestStreamHandler {
 
     private final ValidateController validateController;
-    Logger log = LogManager.getLogger(HandlerStream.class);
+    Logger log = LoggerFactory.getLogger(HandlerStream.class);
 
     public HandlerStream() {
         log.info("Creating the Validator instance for the first time...");
@@ -55,15 +55,15 @@ public void handleRequest(InputStream inputStream, OutputStream outputStream, Co
             JsonObject jsonPayload = JsonParser.parseString(rawInput).getAsJsonObject();
             JsonObject headers = jsonPayload.get("headers").getAsJsonObject();
             String xRequestID = headers.get("x-request-id") == null ? "" : headers.get("x-request-id").getAsString();
-            LoggingUtils.appendKey("x-request-id", xRequestID);
+            MDC.put("x-request-id", xRequestID);
             String nhsdCorrelationID = headers.get("nhsd-correlation-id") == null ? "" : headers.get("nhsd-correlation-id").getAsString();
-            LoggingUtils.appendKey("nhsd-correlation-id", nhsdCorrelationID);
+            MDC.put("nhsd-correlation-id", nhsdCorrelationID);
             String nhsdRequestID = headers.get("nhsd-request-id") == null ? "" : headers.get("nhsd-request-id").getAsString();
-            LoggingUtils.appendKey("nhsd-request-id", nhsdRequestID);
+            MDC.put("nhsd-request-id", nhsdRequestID);
             String xCorrelationID = headers.get("x-correlation-id") == null ? "" : headers.get("x-correlation-id").getAsString();
-            LoggingUtils.appendKey("x-correlation-id", xCorrelationID);
+            MDC.put("x-correlation-id", xCorrelationID);
             String apigwRequestID = headers.get("apigw-request-id") == null ? "" : headers.get("apigw-request-id").getAsString();
-            LoggingUtils.appendKey("apigw-request-id", apigwRequestID);
+            MDC.put("apigw-request-id", apigwRequestID);
  
             log.info("Calling validate function");
             String validatorResult = validateController.validate(jsonPayload.get("body").toString());
diff --git a/src/main/java/software/nhs/fhirvalidator/service/CapabilityStatementApplier.java b/src/main/java/software/nhs/fhirvalidator/service/CapabilityStatementApplier.java
index 2859ae11..505a21a1 100644
--- a/src/main/java/software/nhs/fhirvalidator/service/CapabilityStatementApplier.java
+++ b/src/main/java/software/nhs/fhirvalidator/service/CapabilityStatementApplier.java
@@ -1,7 +1,7 @@
 package software.nhs.fhirvalidator.service;
 
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 import org.hl7.fhir.instance.model.api.IBaseResource;
 import org.hl7.fhir.r4.model.CapabilityStatement;
 import org.hl7.fhir.utilities.npm.NpmPackage;
@@ -15,7 +15,7 @@
 public class CapabilityStatementApplier {
     private final List<CapabilityStatement.CapabilityStatementRestResourceComponent> restResources;
 
-    Logger log = LogManager.getLogger(CapabilityStatementApplier.class);
+    Logger log = LoggerFactory.getLogger(CapabilityStatementApplier.class);
 
     public CapabilityStatementApplier(
             ImplementationGuideParser implementationGuideParser,
diff --git a/src/main/java/software/nhs/fhirvalidator/service/ImplementationGuideParser.java b/src/main/java/software/nhs/fhirvalidator/service/ImplementationGuideParser.java
index cd678d87..b70cf634 100644
--- a/src/main/java/software/nhs/fhirvalidator/service/ImplementationGuideParser.java
+++ b/src/main/java/software/nhs/fhirvalidator/service/ImplementationGuideParser.java
@@ -3,8 +3,8 @@
 import ca.uhn.fhir.context.FhirContext;
 import ca.uhn.fhir.parser.IParser;
 
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 import org.hl7.fhir.r4.model.*;
 import org.hl7.fhir.utilities.npm.NpmPackage;
 
@@ -16,7 +16,7 @@ public class ImplementationGuideParser {
 
     private final FhirContext fhirContext;
 
-    Logger log = LogManager.getLogger(ImplementationGuideParser.class);
+    Logger log = LoggerFactory.getLogger(ImplementationGuideParser.class);
 
     public ImplementationGuideParser(FhirContext fhirContext) {
         this.fhirContext = fhirContext;
diff --git a/src/main/java/software/nhs/fhirvalidator/service/MessageDefinitionApplier.java b/src/main/java/software/nhs/fhirvalidator/service/MessageDefinitionApplier.java
index 29123bd6..ecabe7b4 100644
--- a/src/main/java/software/nhs/fhirvalidator/service/MessageDefinitionApplier.java
+++ b/src/main/java/software/nhs/fhirvalidator/service/MessageDefinitionApplier.java
@@ -1,7 +1,7 @@
 package software.nhs.fhirvalidator.service;
 
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 import org.hl7.fhir.instance.model.api.IBaseResource;
 import org.hl7.fhir.r4.model.*;
 import org.hl7.fhir.utilities.npm.NpmPackage;
@@ -16,7 +16,7 @@
 public class MessageDefinitionApplier {
 
     private final List<MessageDefinition> messageDefinitions;
-    Logger log = LogManager.getLogger(MessageDefinitionApplier.class);
+    Logger log = LoggerFactory.getLogger(MessageDefinitionApplier.class);
 
     public MessageDefinitionApplier(
             ImplementationGuideParser implementationGuideParser,
diff --git a/src/main/java/software/nhs/fhirvalidator/util/FhirUtils.java b/src/main/java/software/nhs/fhirvalidator/util/FhirUtils.java
index d27ca8aa..2c9fb2de 100644
--- a/src/main/java/software/nhs/fhirvalidator/util/FhirUtils.java
+++ b/src/main/java/software/nhs/fhirvalidator/util/FhirUtils.java
@@ -3,15 +3,15 @@
 import java.util.ArrayList;
 import java.util.List;
 
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import org.hl7.fhir.instance.model.api.IBaseResource;
 import org.hl7.fhir.instance.model.api.IPrimitiveType;
 import org.hl7.fhir.r4.model.Bundle;
 
 public final class FhirUtils {
-    static Logger log = LogManager.getLogger(FhirUtils.class);
+    static Logger log = LoggerFactory.getLogger(FhirUtils.class);
 
     private FhirUtils() {
         throw new IllegalStateException("Utility class");
diff --git a/src/main/java/software/nhs/fhirvalidator/util/ResourceUtils.java b/src/main/java/software/nhs/fhirvalidator/util/ResourceUtils.java
index fad95105..86c1bc5f 100644
--- a/src/main/java/software/nhs/fhirvalidator/util/ResourceUtils.java
+++ b/src/main/java/software/nhs/fhirvalidator/util/ResourceUtils.java
@@ -4,11 +4,11 @@
 import java.io.IOException;
 import java.io.InputStream;
 
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 public class ResourceUtils {
-    static Logger log = LogManager.getLogger(ResourceUtils.class);
+    static Logger log = LoggerFactory.getLogger(ResourceUtils.class);
 
     private ResourceUtils() {
         throw new IllegalStateException("Utility class");