diff --git a/.gitignore b/.gitignore
index db7b774..a0f76ad 100644
--- a/.gitignore
+++ b/.gitignore
@@ -16,6 +16,9 @@ out/
 ### VS Code ###
 .vscode/
 
+### Kotlin ###
+.kotlin
+
 ### Mac OS ###
 .DS_Store
 
diff --git a/build.gradle.kts b/build.gradle.kts
index db918fa..e082d61 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -1,5 +1,3 @@
-import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
-
 plugins {
     kotlin("jvm") version System.getProperty("kotlin_version")
 }
@@ -12,15 +10,20 @@ allprojects {
 subprojects {
     apply(plugin = "org.jetbrains.kotlin.jvm")
 
+    java {
+        toolchain {
+            languageVersion = JavaLanguageVersion.of(21)
+        }
+    }
+
     dependencies {
         testImplementation("org.jetbrains.kotlin:kotlin-test")
         testImplementation("org.junit.jupiter:junit-jupiter:5.9.3")
     }
 
-    tasks.withType<KotlinCompile> {
-        kotlinOptions {
-            freeCompilerArgs += "-Xjsr305=strict"
-            jvmTarget = "21"
+    kotlin {
+        compilerOptions {
+            freeCompilerArgs.addAll("-Xjsr305=strict")
         }
     }