diff --git a/build.gradle b/build.gradle
index 0b936393a7..4eb678c661 100644
--- a/build.gradle
+++ b/build.gradle
@@ -22,7 +22,7 @@ plugins {
 	id 'maven-publish'
 }
 
-def minecraft_version = "1.15"
+def minecraft_version = "1.15.1-pre1"
 
 def ENV = System.getenv()
 // Fetch build number from Jenkins
diff --git a/mappings/net/minecraft/state/AbstractState.mapping b/mappings/net/minecraft/state/AbstractState.mapping
index d76b5fe0dd..c8f27260f7 100644
--- a/mappings/net/minecraft/state/AbstractState.mapping
+++ b/mappings/net/minecraft/state/AbstractState.mapping
@@ -1,14 +1,11 @@
 CLASS net/minecraft/class_2679 net/minecraft/state/AbstractState
 	FIELD field_12285 entries Lcom/google/common/collect/ImmutableMap;
-	FIELD field_12286 hashCode I
 	FIELD field_12287 owner Ljava/lang/Object;
 	FIELD field_12288 withTable Lcom/google/common/collect/Table;
 	FIELD field_12289 PROPERTY_MAP_PRINTER Ljava/util/function/Function;
 	METHOD <init> (Ljava/lang/Object;Lcom/google/common/collect/ImmutableMap;)V
 		ARG 1 owner
 		ARG 2 entries
-	METHOD equals (Ljava/lang/Object;)Z
-		ARG 1 o
 	METHOD method_11569 getProperties ()Ljava/util/Collection;
 	METHOD method_11570 contains (Lnet/minecraft/class_2769;)Z
 		ARG 1 property
diff --git a/mappings/net/minecraft/world/biome/source/BiomeArray.mapping b/mappings/net/minecraft/world/biome/source/BiomeArray.mapping
index e3328ac903..20ee19516d 100644
--- a/mappings/net/minecraft/world/biome/source/BiomeArray.mapping
+++ b/mappings/net/minecraft/world/biome/source/BiomeArray.mapping
@@ -12,8 +12,6 @@ CLASS net/minecraft/class_4548 net/minecraft/world/biome/source/BiomeArray
 		ARG 1 pos
 		ARG 2 source
 		ARG 3 rawIds
-	METHOD <init> (Lnet/minecraft/class_2540;)V
-		ARG 1 buf
 	METHOD <init> ([Lnet/minecraft/class_1959;)V
 		ARG 1 data
 	METHOD method_22401 toIntArray ()[I