diff --git a/patches/server/0156-PaperPR-Apply-advancements-async.patch b/patches/server/0156-PaperPR-Apply-advancements-async.patch
new file mode 100644
index 000000000..18c5e1972
--- /dev/null
+++ b/patches/server/0156-PaperPR-Apply-advancements-async.patch
@@ -0,0 +1,122 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Mariell Hoversholm <proximyst@proximyst.com>
+Date: Thu, 20 Aug 2020 17:57:02 +0200
+Subject: [PATCH] PaperPR - Apply advancements async
+
+
+diff --git a/src/main/java/net/minecraft/server/AdvancementDataPlayer.java b/src/main/java/net/minecraft/server/AdvancementDataPlayer.java
+index eaa1063ff2..a3b89a4f2a 100644
+--- a/src/main/java/net/minecraft/server/AdvancementDataPlayer.java
++++ b/src/main/java/net/minecraft/server/AdvancementDataPlayer.java
+@@ -63,6 +63,7 @@ public class AdvancementDataPlayer {
+         this.d(advancementdataworld);
+     }
+ 
++    public final void setPlayer(EntityPlayer entityPlayer) { this.a(entityPlayer); } // Paper - OBFHELPER
+     public void a(EntityPlayer entityplayer) {
+         this.player = entityplayer;
+     }
+diff --git a/src/main/java/net/minecraft/server/EntityPlayer.java b/src/main/java/net/minecraft/server/EntityPlayer.java
+index c5d03fd208..a58e7ba6e4 100644
+--- a/src/main/java/net/minecraft/server/EntityPlayer.java
++++ b/src/main/java/net/minecraft/server/EntityPlayer.java
+@@ -49,7 +49,8 @@ public class EntityPlayer extends EntityHuman implements ICrafting {
+     public final MinecraftServer server;
+     public final PlayerInteractManager playerInteractManager;
+     public final Deque<Integer> removeQueue = new ArrayDeque<>(); // Paper
+-    private final AdvancementDataPlayer advancementDataPlayer;
++    private AdvancementDataPlayer advancementDataPlayer; // Paper - remove final
++    private final java.util.concurrent.CompletableFuture<AdvancementDataPlayer> advancementDataPlayerCompletableFuture; // Paper - async advancements
+     private final ServerStatisticManager serverStatisticManager;
+     private float lastHealthScored = Float.MIN_VALUE;
+     private int lastFoodScored = Integer.MIN_VALUE;
+@@ -136,7 +137,7 @@ public class EntityPlayer extends EntityHuman implements ICrafting {
+         this.playerInteractManager = playerinteractmanager;
+         this.server = minecraftserver;
+         this.serverStatisticManager = minecraftserver.getPlayerList().getStatisticManager(this);
+-        this.advancementDataPlayer = minecraftserver.getPlayerList().f(this);
++        this.advancementDataPlayerCompletableFuture = minecraftserver.getPlayerList().loadAdvancementDataPlayerAsync(this); // Paper - async advancements
+         this.G = 1.0F;
+         //this.c(worldserver); // Paper - don't move to spawn on login, only first join
+         this.co = minecraftserver.a(this);
+@@ -505,7 +506,8 @@ public class EntityPlayer extends EntityHuman implements ICrafting {
+             CriterionTriggers.u.a(this, this.cf, this.ticksLived - this.cg);
+         }
+ 
+-        this.advancementDataPlayer.b(this);
++        if (areAdvancementsLoaded()) // Paper - async advancements: don't tick advancements until they're loaded
++            this.advancementDataPlayer.sendUpdateIfNeeded(this); // Paper - conflict on change
+ 
+         // Purpur start
+         if (this.world.purpurConfig.useNightVisionWhenRiding && this.getVehicle() != null && this.getVehicle().getRider() == this && world.getTime() % 100 == 0) { // 5 seconds
+@@ -2121,7 +2123,26 @@ public class EntityPlayer extends EntityHuman implements ICrafting {
+         this.worldChangeInvuln = false;
+     }
+ 
++    // Paper start - async advancements
++    public boolean areAdvancementsLoaded() {
++        return this.advancementDataPlayer != null
++            || this.advancementDataPlayerCompletableFuture.isDone();
++    }
++
++    public AdvancementDataPlayer getAdvancementDataIfLoadedImmediately() {
++        // We need a null check here because this method is called before the future is assigned.
++        // Once assigned, it will essentially be a no-op as the field is final.
++        if (this.advancementDataPlayer == null && this.advancementDataPlayerCompletableFuture != null && this.advancementDataPlayerCompletableFuture.isDone())
++            this.advancementDataPlayer = this.advancementDataPlayerCompletableFuture.join();
++        return this.advancementDataPlayer;
++    }
++
+     public AdvancementDataPlayer getAdvancementData() {
++        if (this.advancementDataPlayer == null)
++            synchronized (this.advancementDataPlayerCompletableFuture) {
++                if (this.advancementDataPlayer == null) this.advancementDataPlayer = this.advancementDataPlayerCompletableFuture.join();
++            }
++        // Paper end
+         return this.advancementDataPlayer;
+     }
+ 
+diff --git a/src/main/java/net/minecraft/server/MinecraftServer.java b/src/main/java/net/minecraft/server/MinecraftServer.java
+index 65dd23d8ec..47265cad93 100644
+--- a/src/main/java/net/minecraft/server/MinecraftServer.java
++++ b/src/main/java/net/minecraft/server/MinecraftServer.java
+@@ -2312,6 +2312,7 @@ public abstract class MinecraftServer extends IAsyncTaskHandlerReentrant<TickTas
+         return methodprofilerresults;
+     }
+ 
++    public final java.nio.file.Path getSavedFilePath(SavedFile savedFile) { return this.a(savedFile); } // Paper - OBFHELPER
+     public java.nio.file.Path a(SavedFile savedfile) {
+         return this.convertable.getWorldFolder(savedfile);
+     }
+diff --git a/src/main/java/net/minecraft/server/PlayerList.java b/src/main/java/net/minecraft/server/PlayerList.java
+index 7b385eb43e..3f634a266f 100644
+--- a/src/main/java/net/minecraft/server/PlayerList.java
++++ b/src/main/java/net/minecraft/server/PlayerList.java
+@@ -1339,9 +1339,26 @@ public abstract class PlayerList {
+         return serverstatisticmanager;
+     }
+ 
++    // Paper start - async advancements
++    public java.util.concurrent.CompletableFuture<AdvancementDataPlayer> loadAdvancementDataPlayerAsync(EntityPlayer entityPlayer) {
++        if (entityPlayer.getAdvancementDataIfLoadedImmediately() != null) {
++            entityPlayer.getAdvancementData().setPlayer(entityPlayer);
++            return java.util.concurrent.CompletableFuture.completedFuture(entityPlayer.getAdvancementData());
++        }
++
++        UUID uuid = entityPlayer.getUniqueID();
++        File file = this.server.getSavedFilePath(SavedFile.ADVANCEMENTS).toFile();
++        final File file1 = new File(file, uuid + ".json");
++        return java.util.concurrent.CompletableFuture.supplyAsync(
++            () -> new AdvancementDataPlayer(this.server.getDataFixer(), this, this.server.getAdvancementData(), file1, entityPlayer),
++            server.executorService
++        );
++    }
++    // Paper end
++
+     public AdvancementDataPlayer f(EntityPlayer entityplayer) {
+         UUID uuid = entityplayer.getUniqueID();
+-        AdvancementDataPlayer advancementdataplayer = (AdvancementDataPlayer) entityplayer.getAdvancementData(); // CraftBukkit
++        AdvancementDataPlayer advancementdataplayer = (AdvancementDataPlayer) entityplayer.getAdvancementDataIfLoadedImmediately(); // CraftBukkit // Paper
+ 
+         if (advancementdataplayer == null) {
+             File file = this.server.a(SavedFile.ADVANCEMENTS).toFile();