diff --git a/paper-api/pom.xml b/paper-api/pom.xml
index b3fb45961f..a99e049851 100644
--- a/paper-api/pom.xml
+++ b/paper-api/pom.xml
@@ -5,7 +5,7 @@
 
     <groupId>org.bukkit</groupId>
     <artifactId>bukkit</artifactId>
-    <version>1.15.1-R0.1-SNAPSHOT</version>
+    <version>1.15.2-R0.1-SNAPSHOT</version>
     <packaging>jar</packaging>
 
     <name>Bukkit</name>
@@ -80,7 +80,7 @@
         <!-- annotations -->
         <dependency>
             <groupId>org.jetbrains</groupId>
-            <artifactId>annotations-java5</artifactId>
+            <artifactId>annotations</artifactId>
             <version>18.0.0</version>
             <scope>provided</scope>
         </dependency>
@@ -88,7 +88,7 @@
         <dependency>
             <groupId>junit</groupId>
             <artifactId>junit</artifactId>
-            <version>4.12</version>
+            <version>4.13</version>
             <scope>test</scope>
         </dependency>
         <dependency>
@@ -100,7 +100,7 @@
         <dependency>
             <groupId>org.ow2.asm</groupId>
             <artifactId>asm-tree</artifactId>
-            <version>7.2</version>
+            <version>7.3.1</version>
             <scope>test</scope>
         </dependency>
     </dependencies>
diff --git a/paper-api/src/main/java/org/bukkit/GameRule.java b/paper-api/src/main/java/org/bukkit/GameRule.java
index 81a9630ea4..48f8dd6495 100644
--- a/paper-api/src/main/java/org/bukkit/GameRule.java
+++ b/paper-api/src/main/java/org/bukkit/GameRule.java
@@ -148,6 +148,16 @@ public final class GameRule<T> {
      */
     public static final GameRule<Boolean> FIRE_DAMAGE = new GameRule<>("fireDamage", Boolean.class);
 
+    /**
+     * Whether patrols should naturally spawn.
+     */
+    public static final GameRule<Boolean> DO_PATROL_SPAWNING = new GameRule<>("doPatrolSpawning", Boolean.class);
+
+    /**
+     * Whether traders should naturally spawn.
+     */
+    public static final GameRule<Boolean> DO_TRADER_SPAWNING = new GameRule<>("doTraderSpawning", Boolean.class);
+
     // Numerical rules
     /**
      * How often a random block tick occurs (such as plant growth, leaf decay,
diff --git a/paper-api/src/main/java/org/bukkit/inventory/ItemStack.java b/paper-api/src/main/java/org/bukkit/inventory/ItemStack.java
index bab86d8049..9d9df827b5 100644
--- a/paper-api/src/main/java/org/bukkit/inventory/ItemStack.java
+++ b/paper-api/src/main/java/org/bukkit/inventory/ItemStack.java
@@ -16,7 +16,11 @@ import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
 /**
- * Represents a stack of items
+ * Represents a stack of items.
+ * <p>
+ * <b>IMPORTANT: An <i>Item</i>Stack is only designed to contain <i>items</i>. Do not
+ * use this class to encapsulate Materials for which {@link Material#isItem()}
+ * returns false.</b>
  */
 public class ItemStack implements Cloneable, ConfigurationSerializable {
     private Material type = Material.AIR;
@@ -28,7 +32,11 @@ public class ItemStack implements Cloneable, ConfigurationSerializable {
     protected ItemStack() {}
 
     /**
-     * Defaults stack size to 1, with no extra data
+     * Defaults stack size to 1, with no extra data.
+     * <p>
+     * <b>IMPORTANT: An <i>Item</i>Stack is only designed to contain
+     * <i>items</i>. Do not use this class to encapsulate Materials for which
+     * {@link Material#isItem()} returns false.</b>
      *
      * @param type item material
      */
@@ -37,7 +45,11 @@ public class ItemStack implements Cloneable, ConfigurationSerializable {
     }
 
     /**
-     * An item stack with no extra data
+     * An item stack with no extra data.
+     * <p>
+     * <b>IMPORTANT: An <i>Item</i>Stack is only designed to contain
+     * <i>items</i>. Do not use this class to encapsulate Materials for which
+     * {@link Material#isItem()} returns false.</b>
      *
      * @param type item material
      * @param amount stack size
@@ -109,7 +121,11 @@ public class ItemStack implements Cloneable, ConfigurationSerializable {
     /**
      * Sets the type of this item
      * <p>
-     * Note that in doing so you will reset the MaterialData for this stack
+     * Note that in doing so you will reset the MaterialData for this stack.
+     * <p>
+     * <b>IMPORTANT: An <i>Item</i>Stack is only designed to contain
+     * <i>items</i>. Do not use this class to encapsulate Materials for which
+     * {@link Material#isItem()} returns false.</b>
      *
      * @param type New type to set the items in this stack to
      */