diff --git a/.forgejo/workflows/build.yml b/.forgejo/workflows/build.yml
index 5afcc3c..e62a601 100644
--- a/.forgejo/workflows/build.yml
+++ b/.forgejo/workflows/build.yml
@@ -13,6 +13,8 @@ jobs:
       - name: Download NMS
         run: ./tools/download_nms.sh ~
 
+      - name: Build for 1.21.5
+        run: ./mvnw package -Dproject.minecraft.version=1.21.5 -Dproject.craftbukkit.version=v1_21_R4
 
       - name: Build for 1.21.4
         run: ./mvnw package -Dproject.minecraft.version=1.21.4 -Dproject.craftbukkit.version=v1_21_R3
diff --git a/pom.xml b/pom.xml
index 7c04e18..7a206ae 100644
--- a/pom.xml
+++ b/pom.xml
@@ -17,8 +17,8 @@
         <maven.compiler.target>21</maven.compiler.target>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
 
-        <project.craftbukkit.version>v1_21_R3</project.craftbukkit.version>
-        <project.minecraft.version>1.21.4</project.minecraft.version>
+        <project.craftbukkit.version>v1_21_R4</project.craftbukkit.version>
+        <project.minecraft.version>1.21.5</project.minecraft.version>
         <project.spigot.version>${project.minecraft.version}-R0.1-SNAPSHOT</project.spigot.version>
     </properties>
 
@@ -44,7 +44,7 @@
                         </goals>
                         <configuration>
                             <target>
-                                <replace token="v1_21_R3" value="${project.craftbukkit.version}" dir="src/main">
+                                <replace token="v1_21_R4" value="${project.craftbukkit.version}" dir="src/main">
                                     <include name="**/*.java" />
                                 </replace>
                             </target>
@@ -58,7 +58,7 @@
                         </goals>
                         <configuration>
                             <target>
-                                <replace token="${project.craftbukkit.version}" value="v1_21_R3" dir="src/main">
+                                <replace token="${project.craftbukkit.version}" value="v1_21_R4" dir="src/main">
                                     <include name="**/*.java" />
                                 </replace>
                             </target>
@@ -128,7 +128,7 @@
         <dependency>
             <groupId>org.spigotmc</groupId>
             <artifactId>spigot-api</artifactId>
-            <version>1.21.1-R0.1-SNAPSHOT</version>
+            <version>1.21.1-R0.1-SNAPSHOT</version> <!-- oldest supported version -->
             <scope>provided</scope>
         </dependency>
         <dependency>
diff --git a/src/main/java/eu/m724/tweaks/module/chat/ChatListener.java b/src/main/java/eu/m724/tweaks/module/chat/ChatListener.java
index 21b65f9..5b80556 100644
--- a/src/main/java/eu/m724/tweaks/module/chat/ChatListener.java
+++ b/src/main/java/eu/m724/tweaks/module/chat/ChatListener.java
@@ -14,8 +14,8 @@ import net.md_5.bungee.api.chat.TextComponent;
 import net.md_5.bungee.api.chat.TranslatableComponent;
 import net.md_5.bungee.chat.ComponentSerializer;
 import net.minecraft.network.chat.Component;
-import org.bukkit.craftbukkit.v1_21_R3.CraftRegistry;
-import org.bukkit.craftbukkit.v1_21_R3.entity.CraftPlayer;
+import org.bukkit.craftbukkit.v1_21_R4.CraftRegistry;
+import org.bukkit.craftbukkit.v1_21_R4.entity.CraftPlayer;
 import org.bukkit.entity.Player;
 import org.bukkit.event.EventHandler;
 import org.bukkit.event.Listener;
diff --git a/src/main/java/eu/m724/tweaks/module/worldborder/WorldBorderExpandModule.java b/src/main/java/eu/m724/tweaks/module/worldborder/WorldBorderExpandModule.java
index b4a4a30..acf14b2 100644
--- a/src/main/java/eu/m724/tweaks/module/worldborder/WorldBorderExpandModule.java
+++ b/src/main/java/eu/m724/tweaks/module/worldborder/WorldBorderExpandModule.java
@@ -8,7 +8,7 @@ package eu.m724.tweaks.module.worldborder;
 
 import eu.m724.tweaks.module.TweaksModule;
 import net.minecraft.server.level.ServerLevel;
-import org.bukkit.craftbukkit.v1_21_R3.CraftWorld;
+import org.bukkit.craftbukkit.v1_21_R4.CraftWorld;
 import org.bukkit.event.EventHandler;
 import org.bukkit.event.Listener;
 import org.bukkit.event.world.WorldLoadEvent;
diff --git a/tools/download_nms.sh b/tools/download_nms.sh
index 95a44be..87a2bf7 100755
--- a/tools/download_nms.sh
+++ b/tools/download_nms.sh
@@ -1,15 +1,10 @@
 #!/bin/sh
 
-#
-# Copyright (C) 2025  Minecon724
-# Tweaks724 is licensed under the GNU General Public License. See the LICENSE.md file
-# in the project root for the full license text.
-#
-
-FILENAME=MS4yMS4xLTQK.tar.zst
+FILENAME=nms_1_21_1+3+4+5.tar.zst
+CHECKSUM=0ea6267ce39213ddb0d6a7669d8021283350bb56de0d65f2e9fddd3c85337c5fbd204272b07c7e8532c6eaef46c3a47a39bac183abd6f4cfa7b171e08b4d7029
 
 curl -O https://36ab09b1.m724.eu/$FILENAME
-if [ "$(sha512sum $FILENAME)" = "475b931b6dde126aafd3f959bd02e122aa3c671ad11e83cbe1a9c9ea771a424f203381aa31e4ab40052dae1bfbe96c61daa81add1afab46dd423a5f038d68a6b  MS4yMS4xLTQK.tar.zst" ]; then
+if [ "$(sha512sum $FILENAME)" = "$CHECKSUM  $FILENAME" ]; then
   tar -xaf $FILENAME -C "$1"
   rm $FILENAME
 else