diff --git a/Movecraft/build.gradle.kts b/Movecraft/build.gradle.kts
index 3574d461f..05e79516c 100644
--- a/Movecraft/build.gradle.kts
+++ b/Movecraft/build.gradle.kts
@@ -66,7 +66,7 @@ hangarPublish {
         platforms {
             register(io.papermc.hangarpublishplugin.model.Platforms.PAPER) {
                 jar.set(tasks.shadowJar.flatMap { it.archiveFile })
-                platformVersions.set(listOf("1.20.6", "1.21.1"))
+                platformVersions.set(listOf("1.20.6", "1.21.3"))
             }
         }
     }
diff --git a/v1_21/build.gradle.kts b/v1_21/build.gradle.kts
index d84125889..2f8167e50 100644
--- a/v1_21/build.gradle.kts
+++ b/v1_21/build.gradle.kts
@@ -7,7 +7,7 @@ java.toolchain.languageVersion = JavaLanguageVersion.of(21)
 
 dependencies {
     api(project(":movecraft-api"))
-    paperweight.paperDevBundle("1.21.1-R0.1-SNAPSHOT")
+    paperweight.paperDevBundle("1.21.3-R0.1-SNAPSHOT")
 }
 
 description = "Movecraft-v1_21"
diff --git a/v1_21/src/main/java/net/countercraft/movecraft/compat/v1_21/IWorldHandler.java b/v1_21/src/main/java/net/countercraft/movecraft/compat/v1_21/IWorldHandler.java
index d4e3cba4b..f04ab98a1 100644
--- a/v1_21/src/main/java/net/countercraft/movecraft/compat/v1_21/IWorldHandler.java
+++ b/v1_21/src/main/java/net/countercraft/movecraft/compat/v1_21/IWorldHandler.java
@@ -1,5 +1,6 @@
 package net.countercraft.movecraft.compat.v1_21;
 
+import ca.spottedleaf.moonrise.common.util.WorldUtil;
 import net.countercraft.movecraft.MovecraftLocation;
 import net.countercraft.movecraft.MovecraftRotation;
 import net.countercraft.movecraft.WorldHandler;
@@ -51,7 +52,7 @@ public class IWorldHandler extends WorldHandler {
 
     public IWorldHandler() {
         String version = Bukkit.getServer().getMinecraftVersion();
-        if (!version.equals("1.21.1"))
+        if (!version.equals("1.21.3"))
             throw new IllegalStateException("Movecraft is not compatible with this version of Minecraft: " + version);
     }
 
@@ -237,7 +238,7 @@ private BlockPos locationToPosition(@NotNull MovecraftLocation loc) {
 
     private void setBlockFast(@NotNull Level world, @NotNull BlockPos position, @NotNull BlockState data) {
         LevelChunk chunk = world.getChunkAt(position);
-        int chunkSection = (position.getY() >> 4) - chunk.getMinSection();
+        int chunkSection = (position.getY() >> 4) - WorldUtil.getMinSection(world);
         LevelChunkSection section = chunk.getSections()[chunkSection];
         if (section == null) {
             // Put a GLASS block to initialize the section. It will be replaced next with the real block.
@@ -251,7 +252,7 @@ private void setBlockFast(@NotNull Level world, @NotNull BlockPos position, @Not
         section.setBlockState(position.getX() & 15, position.getY() & 15, position.getZ() & 15, data);
         world.sendBlockUpdated(position, data, data, 3);
         world.getLightEngine().checkBlock(position); // boolean corresponds to if chunk section empty
-        chunk.setUnsaved(true);
+        chunk.markUnsaved();
     }
 
     @Override