diff --git a/spring-boot-project/spring-boot-dependencies/build.gradle b/spring-boot-project/spring-boot-dependencies/build.gradle
index d178e5c3279..c16c9eaf2b3 100644
--- a/spring-boot-project/spring-boot-dependencies/build.gradle
+++ b/spring-boot-project/spring-boot-dependencies/build.gradle
@@ -1121,7 +1121,7 @@ bom {
 			releaseNotes("https://github.com/apache/logging-log4j2/releases/tag/rel%2F{version}")
 		}
 	}
-	library("Logback", "1.5.7") {
+	library("Logback", "1.5.6") {
 		group("ch.qos.logback") {
 			modules = [
 				"logback-classic",
diff --git a/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/logging/logback/DefaultLogbackConfiguration.java b/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/logging/logback/DefaultLogbackConfiguration.java
index 6712419f81a..abba6c24c41 100644
--- a/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/logging/logback/DefaultLogbackConfiguration.java
+++ b/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/logging/logback/DefaultLogbackConfiguration.java
@@ -17,7 +17,6 @@
 package org.springframework.boot.logging.logback;
 
 import java.nio.charset.Charset;
-import java.util.concurrent.locks.ReentrantLock;
 
 import ch.qos.logback.classic.Level;
 import ch.qos.logback.classic.encoder.PatternLayoutEncoder;
@@ -45,7 +44,6 @@ import org.springframework.boot.logging.LogFile;
  * @author Robert Thornton
  * @author Scott Frederick
  * @author Jonatan Ivanov
- * @author Mark Chesney
  */
 class DefaultLogbackConfiguration {
 
@@ -56,9 +54,7 @@ class DefaultLogbackConfiguration {
 	}
 
 	void apply(LogbackConfigurator config) {
-		ReentrantLock lock = config.getConfigurationLock();
-		lock.lock();
-		try {
+		synchronized (config.getConfigurationLock()) {
 			defaults(config);
 			Appender<ILoggingEvent> consoleAppender = consoleAppender(config);
 			if (this.logFile != null) {
@@ -69,9 +65,6 @@ class DefaultLogbackConfiguration {
 				config.root(Level.INFO, consoleAppender);
 			}
 		}
-		finally {
-			lock.unlock();
-		}
 	}
 
 	private void defaults(LogbackConfigurator config) {
diff --git a/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/logging/logback/LogbackConfigurator.java b/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/logging/logback/LogbackConfigurator.java
index a64f1ce1f54..b57e5d80dbf 100644
--- a/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/logging/logback/LogbackConfigurator.java
+++ b/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/logging/logback/LogbackConfigurator.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2024 the original author or authors.
+ * Copyright 2012-2023 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,7 +18,6 @@ package org.springframework.boot.logging.logback;
 
 import java.util.HashMap;
 import java.util.Map;
-import java.util.concurrent.locks.ReentrantLock;
 
 import ch.qos.logback.classic.Level;
 import ch.qos.logback.classic.Logger;
@@ -50,7 +49,7 @@ class LogbackConfigurator {
 		return this.context;
 	}
 
-	ReentrantLock getConfigurationLock() {
+	Object getConfigurationLock() {
 		return this.context.getConfigurationLock();
 	}
 
diff --git a/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/logging/logback/LogbackLoggingSystemParallelInitializationTests.java b/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/logging/logback/LogbackLoggingSystemParallelInitializationTests.java
index 0e98609fb1e..4624be2a509 100644
--- a/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/logging/logback/LogbackLoggingSystemParallelInitializationTests.java
+++ b/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/logging/logback/LogbackLoggingSystemParallelInitializationTests.java
@@ -45,7 +45,6 @@ class LogbackLoggingSystemParallelInitializationTests {
 	void cleanUp() {
 		this.loggingSystem.cleanUp();
 		((LoggerContext) LoggerFactory.getILoggerFactory()).stop();
-		((LoggerContext) LoggerFactory.getILoggerFactory()).reset();
 	}
 
 	@Test
diff --git a/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/logging/logback/LogbackLoggingSystemTests.java b/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/logging/logback/LogbackLoggingSystemTests.java
index 7e398938d8c..995c25f8804 100644
--- a/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/logging/logback/LogbackLoggingSystemTests.java
+++ b/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/logging/logback/LogbackLoggingSystemTests.java
@@ -128,7 +128,6 @@ class LogbackLoggingSystemTests extends AbstractLoggingSystemTests {
 		System.getProperties().keySet().retainAll(this.systemPropertyNames);
 		this.loggingSystem.cleanUp();
 		((LoggerContext) LoggerFactory.getILoggerFactory()).stop();
-		((LoggerContext) LoggerFactory.getILoggerFactory()).reset();
 	}
 
 	@Test
diff --git a/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/logging/logback/SpringBootJoranConfiguratorTests.java b/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/logging/logback/SpringBootJoranConfiguratorTests.java
index 28d3c930e78..beab88321a3 100644
--- a/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/logging/logback/SpringBootJoranConfiguratorTests.java
+++ b/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/logging/logback/SpringBootJoranConfiguratorTests.java
@@ -72,7 +72,6 @@ class SpringBootJoranConfiguratorTests {
 	@AfterEach
 	void reset() {
 		this.context.stop();
-		this.context.reset();
 		new BasicConfigurator().configure((LoggerContext) LoggerFactory.getILoggerFactory());
 	}