diff --git a/build.gradle b/build.gradle
index 41198dbe73..e4879f4a6a 100644
--- a/build.gradle
+++ b/build.gradle
@@ -2,9 +2,8 @@ buildscript {
 	ext.kotlinVersion = '1.9.25'
 	ext.isCI = System.getenv('GITHUB_ACTION')
 	repositories {
-		mavenCentral()
 		gradlePluginPortal()
-		maven { url 'https://repo.spring.io/plugins-release-local' }
+		mavenCentral()
 		if (version.endsWith('SNAPSHOT')) {
 			maven { url 'https://repo.spring.io/snapshot' }
 		}
@@ -17,12 +16,12 @@ buildscript {
 
 plugins {
 	id 'base'
-	id 'project-report'
 	id 'idea'
 	id 'org.ajoberstar.grgit' version '5.2.2'
 	id 'io.spring.nohttp' version '0.0.11'
 	id 'io.spring.dependency-management' version '1.1.6' apply false
 	id 'com.github.spotbugs' version '6.0.19'
+	id 'io.freefair.aggregate-javadoc' version '8.6'
 }
 
 apply plugin: 'io.spring.nohttp'
@@ -122,29 +121,44 @@ allprojects {
 
 configure(javaProjects) { subproject ->
 	apply plugin: 'java-library'
-	apply plugin: 'java'
-	apply from: "${rootProject.projectDir}/gradle/publish-maven.gradle"
 	apply plugin: 'eclipse'
 	apply plugin: 'idea'
 	apply plugin: 'checkstyle'
 	apply plugin: 'kotlin'
 	apply plugin: 'kotlin-spring'
 
+	apply from: "${rootProject.projectDir}/gradle/publish-maven.gradle"
+
+	def scopeAttribute = Attribute.of('dependency.scope', String)
+
+	configurations {
+		optional {
+			attributes {
+				attribute(scopeAttribute, 'optional')
+			}
+		}
+
+		compileClasspath.extendsFrom(optional)
+		testCompileClasspath.extendsFrom(optional)
+		testRuntimeClasspath.extendsFrom(optional)
+	}
+
+	components.java.addVariantsFromConfiguration(configurations.optional) {
+		mapToOptional()
+	}
+
 	java {
 		withJavadocJar()
 		withSourcesJar()
-		registerFeature('optional') {
-			usingSourceSet(sourceSets.main)
-		}
 	}
 
 	compileJava {
-		sourceCompatibility = 17
-		targetCompatibility = 17
+		options.release = 17
 	}
 
 	compileTestJava {
-		sourceCompatibility = 17
+		sourceCompatibility = JavaVersion.VERSION_17
+		targetCompatibility = JavaVersion.VERSION_17
 		options.encoding = 'UTF-8'
 	}
 
@@ -152,6 +166,10 @@ configure(javaProjects) { subproject ->
 
 	// dependencies that are common across all java projects
 	dependencies {
+		attributesSchema {
+			attribute(scopeAttribute)
+		}
+
 		def spotbugsAnnotations = "com.github.spotbugs:spotbugs-annotations:${spotbugs.toolVersion.get()}"
 		compileOnly spotbugsAnnotations
 		testCompileOnly spotbugsAnnotations
@@ -171,7 +189,7 @@ configure(javaProjects) { subproject ->
 			exclude group: 'org.hamcrest'
 		}
 		testImplementation "org.hamcrest:hamcrest-core:$hamcrestVersion"
-		optionalApi "org.assertj:assertj-core:$assertjVersion"
+		optional "org.assertj:assertj-core:$assertjVersion"
 	}
 
 	// enable all compiler warnings; individual projects may customize further
@@ -188,7 +206,6 @@ configure(javaProjects) { subproject ->
 
 		maxHeapSize = '1536m'
 		useJUnitPlatform()
-
 	}
 
 	checkstyle {
@@ -205,7 +222,7 @@ configure(javaProjects) { subproject ->
 		}
 	}
 
-	task updateCopyrights {
+	tasks.register('updateCopyrights') {
 		onlyIf { !isCI }
 		inputs.files(modifiedFiles.filter { f -> f.path.contains(subproject.name) })
 		outputs.dir('build/classes')
@@ -278,29 +295,29 @@ project ('spring-kafka') {
 			exclude group: 'org.springframework'
 		}
 		api "org.apache.kafka:kafka-clients:$kafkaVersion"
-		optionalApi "org.apache.kafka:kafka-streams:$kafkaVersion"
-		optionalApi "org.jetbrains.kotlinx:kotlinx-coroutines-reactor:$kotlinCoroutinesVersion"
-		optionalApi 'com.fasterxml.jackson.core:jackson-core'
-		optionalApi 'com.fasterxml.jackson.core:jackson-databind'
-		optionalApi 'com.fasterxml.jackson.datatype:jackson-datatype-jdk8'
-		optionalApi 'com.fasterxml.jackson.datatype:jackson-datatype-jsr310'
-		optionalApi 'com.fasterxml.jackson.datatype:jackson-datatype-joda'
-		optionalApi ('com.fasterxml.jackson.module:jackson-module-kotlin') {
+		api 'io.micrometer:micrometer-observation'
+		optional "org.apache.kafka:kafka-streams:$kafkaVersion"
+		optional "org.jetbrains.kotlinx:kotlinx-coroutines-reactor:$kotlinCoroutinesVersion"
+		optional 'com.fasterxml.jackson.core:jackson-core'
+		optional 'com.fasterxml.jackson.core:jackson-databind'
+		optional 'com.fasterxml.jackson.datatype:jackson-datatype-jdk8'
+		optional 'com.fasterxml.jackson.datatype:jackson-datatype-jsr310'
+		optional 'com.fasterxml.jackson.datatype:jackson-datatype-joda'
+		optional ('com.fasterxml.jackson.module:jackson-module-kotlin') {
 			exclude group: 'org.jetbrains.kotlin'
 		}
 
 		// Spring Data projection message binding support
-		optionalApi ("org.springframework.data:spring-data-commons") {
+		optional ("org.springframework.data:spring-data-commons") {
 			exclude group: 'org.springframework'
 			exclude group: 'io.micrometer'
 		}
-		optionalApi "com.jayway.jsonpath:json-path:$jaywayJsonPathVersion"
+		optional "com.jayway.jsonpath:json-path:$jaywayJsonPathVersion"
 
-		optionalApi 'io.projectreactor:reactor-core'
-		optionalApi 'io.projectreactor.kafka:reactor-kafka'
-		optionalApi 'io.micrometer:micrometer-core'
-		api 'io.micrometer:micrometer-observation'
-		optionalApi 'io.micrometer:micrometer-tracing'
+		optional 'io.projectreactor:reactor-core'
+		optional 'io.projectreactor.kafka:reactor-kafka'
+		optional 'io.micrometer:micrometer-core'
+		optional 'io.micrometer:micrometer-tracing'
 
 		testImplementation project (':spring-kafka-test')
 		testImplementation 'io.projectreactor:reactor-test'
@@ -326,9 +343,7 @@ project('spring-kafka-bom') {
 	dependencies {
 		constraints {
 			javaProjects.sort { "$it.name" }.each {
-				if (it.name != 'spring-kafka-docs') {
-					api it
-				}
+				api it
 			}
 		}
 	}
@@ -369,12 +384,12 @@ project ('spring-kafka-test') {
 		}
 		api 'org.junit.jupiter:junit-jupiter-api'
 		api 'org.junit.platform:junit-platform-launcher'
-		optionalApi "org.hamcrest:hamcrest-core:$hamcrestVersion"
-		optionalApi "org.mockito:mockito-core:$mockitoVersion"
-		optionalApi ("junit:junit:$junit4Version") {
+		optional "org.hamcrest:hamcrest-core:$hamcrestVersion"
+		optional "org.mockito:mockito-core:$mockitoVersion"
+		optional ("junit:junit:$junit4Version") {
 			exclude group: 'org.hamcrest', module: 'hamcrest-core'
 		}
-		optionalApi "org.apache.logging.log4j:log4j-core:$log4jVersion"
+		optional "org.apache.logging.log4j:log4j-core:$log4jVersion"
 	}
 }
 
@@ -406,15 +421,19 @@ tasks.register('filterMetricsDocsContent', Copy) {
 	filter { line -> line.replaceAll('org.springframework.kafka.support.micrometer.', '').replaceAll('^Fully qualified n', 'N') }
 }
 
-tasks.register('api', Javadoc) {
-	group = 'Documentation'
-	description = 'Generates aggregated Javadoc API documentation.'
+dependencies {
+	javaProjects.each {
+		javadoc it
+	}
+}
+
+javadoc {
 	title = "${rootProject.description} ${version} API"
 	options {
 		encoding = 'UTF-8'
-		memberLevel = org.gradle.external.javadoc.JavadocMemberLevel.PROTECTED
+		memberLevel = JavadocMemberLevel.PROTECTED
 		author = true
-		header = rootProject.description
+		header = project.description
 		use = true
 		overview = 'src/api/overview.html'
 		splitIndex = true
@@ -422,14 +441,14 @@ tasks.register('api', Javadoc) {
 		addBooleanOption('Xdoclint:syntax', true) // only check syntax with doclint
 	}
 
-	source javaProjects.collect { project ->
-		project.sourceSets.main.allJava
-	}
-
-	classpath = files(javaProjects.collect { project ->
-		project.sourceSets.main.compileClasspath
-	})
 	destinationDir = file('build/api')
+	classpath = files().from { files(javaProjects.collect { it.sourceSets.main.compileClasspath }) }
+}
+
+tasks.register('api') {
+	group = 'Documentation'
+	description = 'Generates aggregated Javadoc API documentation.'
+	dependsOn javadoc
 }
 
 tasks.register('docsZip', Zip) {
@@ -442,7 +461,7 @@ tasks.register('docsZip', Zip) {
 		include 'changelog.txt'
 	}
 
-	from(api) {
+	from(javadoc) {
 		into 'api'
 	}
 }
diff --git a/gradle/docs.gradle b/gradle/docs.gradle
index 11a679bf49..cd8b83a708 100644
--- a/gradle/docs.gradle
+++ b/gradle/docs.gradle
@@ -1,36 +1,37 @@
-node {
-	version = '16.16.0'
-}
-
 antora {
 	version = '3.2.0-alpha.2'
 	playbook = file('src/main/antora/antora-playbook.yml')
-	options = ['to-dir' : project.layout.buildDirectory.dir('site').get().toString(), clean: true, fetch: !project.gradle.startParameter.offline, stacktrace: true]
+	options = [
+			'to-dir'  : project.layout.buildDirectory.dir('site').get().toString(),
+			clean     : true,
+			fetch     : !project.gradle.startParameter.offline,
+			stacktrace: true
+	]
 	dependencies = [
-			'@antora/atlas-extension': '1.0.0-alpha.1',
-			'@antora/collector-extension': '1.0.0-alpha.3',
-			'@asciidoctor/tabs': '1.0.0-beta.3',
-			'@springio/antora-extensions': '1.4.2',
+			'@antora/atlas-extension'         : '1.0.0-alpha.1',
+			'@antora/collector-extension'     : '1.0.0-alpha.3',
+			'@asciidoctor/tabs'               : '1.0.0-beta.3',
+			'@springio/antora-extensions'     : '1.4.2',
 			'@springio/asciidoctor-extensions': '1.0.0-alpha.8',
 	]
 }
 
-tasks.named("generateAntoraYml") {
-	asciidocAttributes = project.provider( {
-		return ['project-version' : project.version,
-				'revnumber': project.version,
-				'spring-version': project.version,
+tasks.named('generateAntoraYml') {
+	asciidocAttributes = project.provider({
+		return ['project-version': project.version,
+				'revnumber'      : project.version,
+				'spring-version' : project.version,
 		]
-	} )
+	})
 	baseAntoraYmlFile = file('src/main/antora/antora.yml')
 }
 
-tasks.create(name: 'createAntoraPartials', type: Sync) {
+tasks.register('createAntoraPartials', Sync) {
 	from { project.rootProject.tasks.filterMetricsDocsContent.outputs }
 	into layout.buildDirectory.dir('generated-antora-resources/modules/ROOT/partials')
 }
 
-tasks.create('generateAntoraResources') {
+tasks.register('generateAntoraResources') {
 	dependsOn 'createAntoraPartials'
 	dependsOn 'generateAntoraYml'
 }
diff --git a/gradle/wrapper/gradle-wrapper.jar b/gradle/wrapper/gradle-wrapper.jar
index d64cd49177..2c3521197d 100644
Binary files a/gradle/wrapper/gradle-wrapper.jar and b/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index db8c3baafe..68e8816d71 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -1,7 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionSha256Sum=9d926787066a081739e8200858338b4a69e837c3a821a33aca9db09dd4a41026
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.5-bin.zip
+distributionSha256Sum=d725d707bfabd4dfdc958c624003b3c80accc03f7037b5122c4b1d0ef15cecab
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.9-bin.zip
 networkTimeout=10000
 validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
diff --git a/gradlew b/gradlew
index 1aa94a4269..f5feea6d6b 100755
--- a/gradlew
+++ b/gradlew
@@ -15,6 +15,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #
+# SPDX-License-Identifier: Apache-2.0
+#
 
 ##############################################################################
 #
@@ -55,7 +57,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/platforms/jvm/plugins-application/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -84,7 +86,8 @@ done
 # shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
 # Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
-APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
+APP_HOME=$( cd -P "${APP_HOME:-./}" > /dev/null && printf '%s
+' "$PWD" ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
diff --git a/gradlew.bat b/gradlew.bat
index 6689b85bee..9b42019c79 100644
--- a/gradlew.bat
+++ b/gradlew.bat
@@ -13,6 +13,8 @@
 @rem See the License for the specific language governing permissions and
 @rem limitations under the License.
 @rem
+@rem SPDX-License-Identifier: Apache-2.0
+@rem
 
 @if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
@@ -43,11 +45,11 @@ set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
 if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -57,11 +59,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail