diff --git a/gradle.properties b/gradle.properties
index 7b75396..b5d2209 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -3,7 +3,7 @@ version = 1.18-R0.1-SNAPSHOT
 
 mcVersion = 1.18
 packageVersion = 1_18_R1
-pufferfishRef = 5bf8730d9a8f621a40ab9b0c7a89f868b6161e28
+pufferfishRef = c4a780fa9439afa4faa194c844514de0f56aa770
 
 org.gradle.jvmargs=-Xmx2G
 
diff --git a/patches/server/0001-Feature-Secure-Seed.patch b/patches/server/0001-Feature-Secure-Seed.patch
index 1ba2401..7f376fc 100644
--- a/patches/server/0001-Feature-Secure-Seed.patch
+++ b/patches/server/0001-Feature-Secure-Seed.patch
@@ -5,7 +5,7 @@ Subject: [PATCH] Feature Secure Seed
 
 
 diff --git a/src/main/java/net/minecraft/server/level/ServerChunkCache.java b/src/main/java/net/minecraft/server/level/ServerChunkCache.java
-index 587855dcd2eb40f89c2a2282c202e9fbef2c7382..cf0cd235511ee099f550c823f5ef0be269c488d8 100644
+index f51fcaba69c9ddc27130ab615526e05b1b4f0e07..1ab2bf2e1b0c77b4b8813da91f614d1c795f7107 100644
 --- a/src/main/java/net/minecraft/server/level/ServerChunkCache.java
 +++ b/src/main/java/net/minecraft/server/level/ServerChunkCache.java
 @@ -49,6 +49,8 @@ import net.minecraft.world.level.storage.LevelStorageSource;
@@ -27,18 +27,18 @@ index 587855dcd2eb40f89c2a2282c202e9fbef2c7382..cf0cd235511ee099f550c823f5ef0be2
      }
  
 diff --git a/src/main/java/net/minecraft/world/entity/monster/Slime.java b/src/main/java/net/minecraft/world/entity/monster/Slime.java
-index 5722d9b30223fb229b80f54d7fb9edf41254a7f7..f0dc9c709659293d5e7b78a5e8f4fa6c5c980a5f 100644
+index 9c440625ce89686b2c250e6aaa62ed83b7015412..4e5b8f73ce9cb807a187c1ace74b14e7d2e94f5a 100644
 --- a/src/main/java/net/minecraft/world/entity/monster/Slime.java
 +++ b/src/main/java/net/minecraft/world/entity/monster/Slime.java
-@@ -336,7 +336,7 @@ public class Slime extends Mob implements Enemy {
+@@ -340,7 +340,7 @@ public class Slime extends Mob implements Enemy {
              }
  
              ChunkPos chunkcoordintpair = new ChunkPos(pos);
 -            boolean flag = world.getMinecraftWorld().paperConfig.allChunksAreSlimeChunks || WorldgenRandom.seedSlimeChunk(chunkcoordintpair.x, chunkcoordintpair.z, ((WorldGenLevel) world).getSeed(), world.getMinecraftWorld().spigotConfig.slimeSeed).nextInt(10) == 0; // Spigot // Paper
 +            boolean flag = world.getMinecraftWorld().paperConfig.allChunksAreSlimeChunks || world.getChunk(chunkcoordintpair.x, chunkcoordintpair.z).isSlimeChunk(); // Spigot // Paper // Matter
  
-             if (random.nextInt(10) == 0 && flag && pos.getY() < 40) {
-                 return checkMobSpawnRules(type, world, spawnReason, pos, random);
+             // Paper start - Replace rules for Height in Slime Chunks
+             final double maxHeightSlimeChunk = world.getMinecraftWorld().paperConfig.slimeMaxSpawnHeightInSlimeChunks;
 diff --git a/src/main/java/net/minecraft/world/level/chunk/ChunkAccess.java b/src/main/java/net/minecraft/world/level/chunk/ChunkAccess.java
 index 5aeaaae6f15050a2da271fe196d0a234ecafc8a1..ea720517a1adfb164d540c2743aaec2a058d13b8 100644
 --- a/src/main/java/net/minecraft/world/level/chunk/ChunkAccess.java