diff --git a/.github/workflows/workflow.yml b/.github/workflows/workflow.yml
index c8d0702..8669fc5 100644
--- a/.github/workflows/workflow.yml
+++ b/.github/workflows/workflow.yml
@@ -16,10 +16,10 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v3
 
-      - name: Set up JDK 17
+      - name: Set up JDK 21
         uses: actions/setup-java@v3
         with:
-          java-version: 17
+          java-version: 21
           distribution: 'adopt'
 
       - name: Cache Gradle dependencies
@@ -54,10 +54,10 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v3
 
-      - name: Set up JDK 17
+      - name: Set up JDK 21
         uses: actions/setup-java@v3
         with:
-          java-version: 17
+          java-version: 21
           distribution: 'adopt'
 
       - name: Cache Gradle dependencies
diff --git a/CHANGELOG.md b/CHANGELOG.md
index f20cf59..50233e8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,12 @@
 # Changelog
 
+## version 0.3.1
+Bump besu dependency to 24.6.0
+- minor trielog factory interface change
+- bump java to 21
+- bump gradle to 8.7.0
+- add hyperledger artifactory repo for besu maven deps
+
 ## version 0.3.0
 this release version uses the final build of 23.10.4-SNAPSHOT
 
diff --git a/build.gradle b/build.gradle
index d48f182..bc0fb9c 100644
--- a/build.gradle
+++ b/build.gradle
@@ -18,6 +18,10 @@ import groovy.transform.Memoized
 buildscript {
     repositories {
         mavenLocal()
+        maven {
+            url "https://hyperledger.jfrog.io/artifactory/besu-maven/"
+            content { includeGroupByRegex('org\\.hyperledger\\.besu\\..*')}
+        }
         mavenCentral()
         maven {
             url "https://artifacts.consensys.net/public/maven/maven/"
@@ -30,7 +34,7 @@ buildscript {
 }
 
 plugins {
-    id 'com.diffplug.spotless' version '6.16.0'
+    id 'com.diffplug.spotless' version '6.21.0'
     id 'com.github.ben-manes.versions' version '0.46.0'
     id 'com.github.hierynomus.license' version '0.16.1'
     id 'io.spring.dependency-management' version '1.1.0'
@@ -53,17 +57,21 @@ group = 'net.consensys.shomei.besu.plugin'
 //version = '0.1.0'
 version = project.hasProperty('releaseVersion') ? project.getProperty('releaseVersion') : 'snapshot'
 
-sourceCompatibility = JavaVersion.VERSION_17
-targetCompatibility = JavaVersion.VERSION_17
+sourceCompatibility = JavaVersion.VERSION_21
+targetCompatibility = JavaVersion.VERSION_21
 
 defaultTasks 'build', 'checkLicenses', 'javadoc', 'plugin'
 
 repositories {
     mavenLocal()
+    maven {
+        url "https://hyperledger.jfrog.io/artifactory/besu-maven/"
+        content { includeGroupByRegex('org\\.hyperledger\\.besu\\..*')}
+    }
     mavenCentral()
     maven {
         url "https://artifacts.consensys.net/public/maven/maven/"
-        content { includeGroupByRegex('tech\\.pegasys($|\\..*)') }
+        content { includeGroupByRegex('tech\\.pegasys($|\\..*)')}
     }
     maven {
         url "https://dl.cloudsmith.io/public/libp2p/jvm-libp2p/maven/"
@@ -88,7 +96,7 @@ spotless {
             exclude '**/build/**'
         }
         removeUnusedImports()
-        googleJavaFormat('1.15.0')
+        googleJavaFormat('1.17.0')
         importOrder 'net.consensys', 'java', ''
         trimTrailingWhitespace()
         endWithNewline()
diff --git a/gradle.properties b/gradle.properties
index 63b0083..a7fd3f9 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -1,2 +1,3 @@
-releaseVersion=0.3.0
-besuVersion=23.10.4-SNAPSHOT
+releaseVersion=0.3.1
+besuVersion=24.6.0
+
diff --git a/gradle/versions.gradle b/gradle/versions.gradle
index 9b2b3a3..52efced 100644
--- a/gradle/versions.gradle
+++ b/gradle/versions.gradle
@@ -35,8 +35,6 @@ dependencyManagement {
         dependency "org.hyperledger.besu:plugin-api:${besuVersion}"
         dependency "org.hyperledger.besu:besu-datatypes:${besuVersion}"
         dependency "org.hyperledger.besu.internal:rlp:${besuVersion}"
-
-
         // Logging dependencies
         dependencySet(group: 'org.apache.logging.log4j', version: '2.20.0') {
             entry 'log4j-api'
@@ -82,7 +80,5 @@ dependencyManagement {
         dependency 'org.assertj:assertj-core:3.24.2'
 
         dependency 'com.google.guava:guava:31.1-jre'
-
-
     }
-}
\ No newline at end of file
+}
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index 4b854e8..a0afe0f 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -1,6 +1,6 @@
 #Wed May 03 13:03:35 PDT 2023
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.0-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/src/main/java/net/consensys/shomei/trielog/ZkTrieLogService.java b/src/main/java/net/consensys/shomei/trielog/ZkTrieLogService.java
index b2c1084..542edeb 100644
--- a/src/main/java/net/consensys/shomei/trielog/ZkTrieLogService.java
+++ b/src/main/java/net/consensys/shomei/trielog/ZkTrieLogService.java
@@ -15,6 +15,7 @@
 package net.consensys.shomei.trielog;
 
 import java.util.List;
+import java.util.Optional;
 import java.util.concurrent.atomic.AtomicReference;
 
 import org.hyperledger.besu.plugin.services.TrieLogService;
@@ -48,8 +49,8 @@ public List<TrieLogEvent.TrieLogObserver> getObservers() {
   }
 
   @Override
-  public TrieLogFactory getTrieLogFactory() {
-    return ZkTrieLogFactory.INSTANCE;
+  public Optional<TrieLogFactory> getTrieLogFactory() {
+    return Optional.of(ZkTrieLogFactory.INSTANCE);
   }
 
   @Override
diff --git a/src/test/java/net/consensys/shomei/rpc/GetShomeiTrieLogsTests.java b/src/test/java/net/consensys/shomei/rpc/GetShomeiTrieLogsTests.java
index e2426fe..2f3a8c7 100644
--- a/src/test/java/net/consensys/shomei/rpc/GetShomeiTrieLogsTests.java
+++ b/src/test/java/net/consensys/shomei/rpc/GetShomeiTrieLogsTests.java
@@ -147,7 +147,7 @@ public void testGetSingleTrieLogIsPresent(VertxTestContext testContext) {
           var res = response.getString("result");
           assertThat(res)
               .isEqualTo(
-                  Bytes.wrap(trieLogService.getTrieLogFactory().serialize(mockLayer))
+                  Bytes.wrap(trieLogService.getTrieLogFactory().get().serialize(mockLayer))
                       .toHexString());
         });
   }