diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index ac45f6dc..b844d4be 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -10,7 +10,7 @@ jobs:
   build:
     strategy:
       matrix:
-        java: [ 17 ]
+        java: [ 21 ]
         os: [ubuntu-22.04, windows-2022]
     runs-on: ${{ matrix.os }}
     steps:
@@ -29,7 +29,7 @@ jobs:
       - name: Build the mod
         run: ./gradlew build
       - name: Upload build artifacts
-        if: ${{ runner.os == 'Linux' && matrix.java == '17' }} # Only upload artifacts from one OS and required JDK.
+        if: ${{ runner.os == 'Linux' && matrix.java == '21' }} # Only upload artifacts from one OS and required JDK.
         uses: actions/upload-artifact@v3
         with:
           name: Artifacts
diff --git a/build.gradle b/build.gradle
index 81093a0f..04a9208b 100644
--- a/build.gradle
+++ b/build.gradle
@@ -7,8 +7,8 @@ plugins {
 	id "com.matthewprenger.cursegradle" version "1.+"
 }
 
-sourceCompatibility = JavaVersion.VERSION_17
-targetCompatibility = JavaVersion.VERSION_17
+sourceCompatibility = JavaVersion.VERSION_21
+targetCompatibility = JavaVersion.VERSION_21
 
 archivesBaseName = project.archives_base_name
 version = project.mod_version
@@ -112,7 +112,7 @@ processResources {
 }
 
 tasks.withType(JavaCompile).configureEach {
-	it.options.release = 17
+	it.options.release = 21
 }
 
 java {
@@ -152,7 +152,7 @@ curseforge {
 		addGameVersion project.minecraft_version
 		addGameVersion 'Quilt'
 		addGameVersion 'Fabric'
-		addGameVersion 'Java 17'
+		addGameVersion 'Java 21'
 		
 		relations {
 			requiredDependency 'fabric-api'
diff --git a/forge/build.gradle b/forge/build.gradle
index 18b77b29..de00e82a 100644
--- a/forge/build.gradle
+++ b/forge/build.gradle
@@ -46,7 +46,7 @@ group = "${maven_group}"
 archivesBaseName = "${archives_base_name}"
 
 println("Specifying Java compatibility...")
-java.toolchain.languageVersion = JavaLanguageVersion.of(17)
+java.toolchain.languageVersion = JavaLanguageVersion.of(21)
 
 println("Java Installation Data:")
 println(" - Java Version: " + System.getProperty('java.version'))
@@ -193,7 +193,7 @@ curseforge {
         changelog = rootProject.file('docs/CHANGELOG.md')
 		
 		addGameVersion project.minecraft_version
-		addGameVersion "Java 17"
+		addGameVersion "Java 21"
 		addGameVersion "Forge"
 		
         //addArtifact(sourcesJar)
diff --git a/neoforge/build.gradle b/neoforge/build.gradle
index 858bb9e9..21ade9f2 100644
--- a/neoforge/build.gradle
+++ b/neoforge/build.gradle
@@ -37,7 +37,7 @@ group = "${maven_group}"
 archivesBaseName = "${archives_base_name}"
 
 println("Specifying Java compatibility...")
-java.toolchain.languageVersion = JavaLanguageVersion.of(17)
+java.toolchain.languageVersion = JavaLanguageVersion.of(21)
 
 println("Java Installation Data:")
 println(" - Java Version: " + System.getProperty('java.version'))
@@ -163,7 +163,7 @@ curseforge {
         changelog = rootProject.file('docs/CHANGELOG.md')
 		
 		addGameVersion project.minecraft_version
-		addGameVersion "Java 17"
+		addGameVersion "Java 21"
 		addGameVersion "NeoForge"
 		
         //addArtifact(sourcesJar)