diff --git a/gradle.properties b/gradle.properties
index d15527d..89a8c32 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -4,15 +4,15 @@ org.gradle.parallel=true
 
 # Fabric Properties
 # check these on https://fabricmc.net/develop
-minecraft_version=1.21
-yarn_mappings=1.21+build.2
-loader_version=0.15.11
+minecraft_version=1.21.5
+yarn_mappings=1.21.5+build.1
+loader_version=0.16.14
 
 # Dependencies
-fabric_version=0.100.1+1.21
+fabric_version=0.123.2+1.21.5
 
 # Mod Properties
 mod_id=randomblockplacement
-mod_version=1.0.0-1.21.0
+mod_version=1.0.0-1.21.5
 maven_group=de.guntram.mcmod.randomblockplacement
 archives_base_name=RandomBlockPlacement
\ No newline at end of file
diff --git a/src/main/java/de/guntram/mcmod/randomblockplacement/RandomBlockPlacement.java b/src/main/java/de/guntram/mcmod/randomblockplacement/RandomBlockPlacement.java
index 026e949..d2285a6 100644
--- a/src/main/java/de/guntram/mcmod/randomblockplacement/RandomBlockPlacement.java
+++ b/src/main/java/de/guntram/mcmod/randomblockplacement/RandomBlockPlacement.java
@@ -1,5 +1,6 @@
 package de.guntram.mcmod.randomblockplacement;
 
+import de.guntram.mcmod.randomblockplacement.mixins.PlayerInventoryAccessor;
 import net.fabricmc.api.ClientModInitializer;
 import net.fabricmc.fabric.api.client.command.v2.ClientCommandRegistrationCallback;
 import net.fabricmc.fabric.api.client.event.lifecycle.v1.ClientTickEvents;
@@ -91,7 +92,7 @@ public void onPlayerInteract() {
             return;
         }
         PlayerInventory inventory = player.getInventory();
-        int index = inventory.selectedSlot;
+        int index = ((PlayerInventoryAccessor) player.getInventory()).getSelectedSlot();
         if (maxSlot >= PlayerInventory.getHotbarSize()) {
             maxSlot = PlayerInventory.getHotbarSize() - 1;
         }
@@ -108,7 +109,7 @@ public void onPlayerInteract() {
                 targetCount -= getBlockCount(inventory, targetSlot);
                 targetSlot++;
             }
-            inventory.selectedSlot = targetSlot;
+            ((PlayerInventoryAccessor) player.getInventory()).setSelectedSlot(targetSlot);
         }
     }
 
diff --git a/src/main/java/de/guntram/mcmod/randomblockplacement/mixins/PlayerInventoryAccessor.java b/src/main/java/de/guntram/mcmod/randomblockplacement/mixins/PlayerInventoryAccessor.java
new file mode 100644
index 0000000..29ac9f0
--- /dev/null
+++ b/src/main/java/de/guntram/mcmod/randomblockplacement/mixins/PlayerInventoryAccessor.java
@@ -0,0 +1,15 @@
+package de.guntram.mcmod.randomblockplacement.mixins;
+
+
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.gen.Accessor;
+import net.minecraft.entity.player.PlayerInventory;
+
+@Mixin(PlayerInventory.class)
+public interface PlayerInventoryAccessor {
+    @Accessor("selectedSlot")
+    int getSelectedSlot();
+
+    @Accessor("selectedSlot")
+    void setSelectedSlot(int slot);
+}
\ No newline at end of file
diff --git a/src/main/resources/mixins.randomblockplacement.json b/src/main/resources/mixins.randomblockplacement.json
index 94a21db..0f4ed0c 100644
--- a/src/main/resources/mixins.randomblockplacement.json
+++ b/src/main/resources/mixins.randomblockplacement.json
@@ -4,7 +4,8 @@
     "refmap": "RandomBlockPlacement-refmap.json",
     "minVersion": "0.6",
     "client": [
-        "PlayerInteractBlockMixin"
+        "PlayerInteractBlockMixin",
+        "PlayerInventoryAccessor"
     ],
     "injectors": {
         "defaultRequire": 1