diff --git a/buildSrc/src/main/java/org/springframework/build/KotlinConventions.java b/buildSrc/src/main/java/org/springframework/build/KotlinConventions.java
index db10992f254..57dd0dcf032 100644
--- a/buildSrc/src/main/java/org/springframework/build/KotlinConventions.java
+++ b/buildSrc/src/main/java/org/springframework/build/KotlinConventions.java
@@ -54,7 +54,7 @@ public class KotlinConventions {
 					"-Xjsr305=strict", // For dependencies using JSR 305
 					"-opt-in=kotlin.RequiresOptIn",
 					"-Xjdk-release=17", // Needed due to https://youtrack.jetbrains.com/issue/KT-49746
-					"-Xannotation-default-target=param-property" // Upcoming default, see https://youtrack.jetbrains.com/issue/KT-73255
+					"-Xannotation-default-target=param-property" // Preferred behavior, default with Kotlin language version set to 2.4+, see https://youtrack.jetbrains.com/issue/KT-73255
 			);
 		});
 	}
diff --git a/gradle.properties b/gradle.properties
index edb3a7bca44..20f44e0eadc 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -4,7 +4,7 @@ org.gradle.caching=true
 org.gradle.jvmargs=-Xmx2048m
 org.gradle.parallel=true
 
-kotlinVersion=2.3.20
+kotlinVersion=2.4.10
 byteBuddyVersion=1.17.6
 
 kotlin.jvm.target.validation.mode=ignore
diff --git a/spring-web/src/test/kotlin/org/springframework/http/codec/json/KotlinSerializationJsonEncoderTests.kt b/spring-web/src/test/kotlin/org/springframework/http/codec/json/KotlinSerializationJsonEncoderTests.kt
index 59bf4c71131..83e6dd247c3 100644
--- a/spring-web/src/test/kotlin/org/springframework/http/codec/json/KotlinSerializationJsonEncoderTests.kt
+++ b/spring-web/src/test/kotlin/org/springframework/http/codec/json/KotlinSerializationJsonEncoderTests.kt
@@ -163,7 +163,7 @@ class KotlinSerializationJsonEncoderTests : AbstractEncoderTests<KotlinSerializa
 			}
 		}
 		val customEncoder = KotlinSerializationJsonEncoder(json)
-		val input = Flux<ISimpleSerializableBean>.just(
+		val input = Flux.just(
 			SimpleSerializableBean("foo"),
 			SimpleSerializableBean("bar"),
 			SimpleSerializableBean("baz")