diff --git a/Changelog.md b/Changelog.md
index ace7f4a..6a838d9 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -1,5 +1,12 @@
 # Upcoming changes
 
+# Version 1.21.2
+
+Refactored checking-if-in-battle code from `O(n)` to `O(1)` complexity.
+(In other words, utilizes the HashMap's constant time lookup of a key instead of
+checking every key's id if the entity's id is the same. This speeds up the
+lookup from linear to constant time.)
+
 # Version 1.21.1
 
 Refactored checking-if-in-battle code to be more efficient.
diff --git a/build.gradle b/build.gradle
index 05f0321..15c0aeb 100644
--- a/build.gradle
+++ b/build.gradle
@@ -14,7 +14,7 @@ apply plugin: 'net.minecraftforge.gradle'
 //apply plugin: 'eclipse'
 //apply plugin: 'maven-publish'
 
-version = "1.21.1"
+version = "1.21.2"
 group = "com.burnedkirby.TurnBasedMinecraft"
 archivesBaseName = "TurnBasedMinecraft"
 
diff --git a/src/main/java/com/burnedkirby/TurnBasedMinecraft/common/BattleManager.java b/src/main/java/com/burnedkirby/TurnBasedMinecraft/common/BattleManager.java
index 688d841..a9cac7f 100644
--- a/src/main/java/com/burnedkirby/TurnBasedMinecraft/common/BattleManager.java
+++ b/src/main/java/com/burnedkirby/TurnBasedMinecraft/common/BattleManager.java
@@ -351,7 +351,7 @@ public class BattleManager
         return result;
     }
 
-    public boolean isInBattle(int entityID) {
-        return entityToBattleMap.keySet().parallelStream().anyMatch(pair -> pair.id == entityID);
+    public boolean isInBattle(Entity entity) {
+        return entityToBattleMap.keySet().contains(new EntityIDDimPair(entity));
     }
 }
\ No newline at end of file
diff --git a/src/main/java/com/burnedkirby/TurnBasedMinecraft/common/HurtEventHandler.java b/src/main/java/com/burnedkirby/TurnBasedMinecraft/common/HurtEventHandler.java
index 5a39f94..f268d3e 100644
--- a/src/main/java/com/burnedkirby/TurnBasedMinecraft/common/HurtEventHandler.java
+++ b/src/main/java/com/burnedkirby/TurnBasedMinecraft/common/HurtEventHandler.java
@@ -9,7 +9,7 @@ public class HurtEventHandler {
         CommonProxy proxy = TurnBasedMinecraftMod.proxy;
         if (event.getEntity().level.isClientSide || proxy.getBattleManager() == null) {
             return;
-        } else if (proxy.getConfig().getIgnoreHurtDamageSources().contains(event.getSource().msgId) && proxy.getBattleManager().isInBattle(event.getEntity().getId())) {
+        } else if (proxy.getConfig().getIgnoreHurtDamageSources().contains(event.getSource().msgId) && proxy.getBattleManager().isInBattle(event.getEntity())) {
             event.setCanceled(true);
         }
     }
diff --git a/src/main/java/com/burnedkirby/TurnBasedMinecraft/common/TurnBasedMinecraftMod.java b/src/main/java/com/burnedkirby/TurnBasedMinecraft/common/TurnBasedMinecraftMod.java
index 53cf919..305a0cc 100644
--- a/src/main/java/com/burnedkirby/TurnBasedMinecraft/common/TurnBasedMinecraftMod.java
+++ b/src/main/java/com/burnedkirby/TurnBasedMinecraft/common/TurnBasedMinecraftMod.java
@@ -39,7 +39,7 @@ import org.apache.logging.log4j.Logger;
 public class TurnBasedMinecraftMod {
     public static final String MODID = "com_burnedkirby_turnbasedminecraft";
     public static final String NAME = "Turn Based Minecraft Mod";
-    public static final String VERSION = "1.21.1";
+    public static final String VERSION = "1.21.2";
     public static final String CONFIG_FILENAME = "TBM_Config.toml";
     public static final String DEFAULT_CONFIG_FILENAME = "TBM_Config_DEFAULT.toml";
     public static final String CONFIG_DIRECTORY = "config/TurnBasedMinecraft/";
diff --git a/src/main/resources/META-INF/mods.toml b/src/main/resources/META-INF/mods.toml
index b172066..3780f3e 100644
--- a/src/main/resources/META-INF/mods.toml
+++ b/src/main/resources/META-INF/mods.toml
@@ -15,7 +15,7 @@ license="MIT"
 # The modid of the mod
 modId="com_burnedkirby_turnbasedminecraft" #mandatory
 # The version number of the mod - there's a few well known ${} variables useable here or just hardcode it
-version="1.21.1" #mandatory
+version="1.21.2" #mandatory
  # A display name for the mod
 displayName="TurnBasedMinecraftMod" #mandatory
 # A URL to query for updates for this mod. See the JSON update specification <here>
diff --git a/src/main/resources/mcmod.info b/src/main/resources/mcmod.info
index bafbd81..5b9cfd0 100644
--- a/src/main/resources/mcmod.info
+++ b/src/main/resources/mcmod.info
@@ -3,7 +3,7 @@
   "modid": "com_burnedkirby_turnbasedminecraft",
   "name": "Turn Based Minecraft",
   "description": "Changes battles to be turn-based.",
-  "version": "1.21.1",
+  "version": "1.21.2",
   "mcversion": "1.18.2",
   "url": "",
   "updateUrl": "",