diff --git a/patches/api/0387-OfflinePlayer-advancements.patch b/patches/api/0387-OfflinePlayer-advancements.patch
new file mode 100644
index 0000000000..453cdc5d48
--- /dev/null
+++ b/patches/api/0387-OfflinePlayer-advancements.patch
@@ -0,0 +1,29 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Jake Potrebic <jake.m.potrebic@gmail.com>
+Date: Thu, 22 Apr 2021 01:42:02 -0700
+Subject: [PATCH] OfflinePlayer advancements
+
+
+diff --git a/src/main/java/org/bukkit/OfflinePlayer.java b/src/main/java/org/bukkit/OfflinePlayer.java
+index a7d1f1e701f23e851f735584a30bedadb0d8b9bd..2946b0432316fff2c77dca303dea297bbda239d5 100644
+--- a/src/main/java/org/bukkit/OfflinePlayer.java
++++ b/src/main/java/org/bukkit/OfflinePlayer.java
+@@ -203,6 +203,18 @@ public interface OfflinePlayer extends ServerOperator, AnimalTamer, Configuratio
+      * @return last seen time
+      */
+     public long getLastSeen();
++
++    /**
++     * Return the player's progression on the specified advancement.
++     * May cause an I/O operation.
++     * <p>
++     * <b>You cannot award criteria to an offline player!</b>
++     *
++     * @param advancement advancement
++     * @return object detailing the player's progress
++     */
++    @NotNull
++    org.bukkit.advancement.AdvancementProgress getAdvancementProgress(@NotNull org.bukkit.advancement.Advancement advancement);
+     // Paper end
+ 
+     /**
diff --git a/patches/server/0918-OfflinePlayer-advancements.patch b/patches/server/0918-OfflinePlayer-advancements.patch
new file mode 100644
index 0000000000..7a905811fe
--- /dev/null
+++ b/patches/server/0918-OfflinePlayer-advancements.patch
@@ -0,0 +1,59 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Jake Potrebic <jake.m.potrebic@gmail.com>
+Date: Thu, 22 Apr 2021 01:41:56 -0700
+Subject: [PATCH] OfflinePlayer advancements
+
+
+diff --git a/src/main/java/net/minecraft/server/players/PlayerList.java b/src/main/java/net/minecraft/server/players/PlayerList.java
+index 20cdfdb3b9351f74e89bc45b3ab972384165659a..2ac7be4855553268b25615d9ee1a8c3206b84b42 100644
+--- a/src/main/java/net/minecraft/server/players/PlayerList.java
++++ b/src/main/java/net/minecraft/server/players/PlayerList.java
+@@ -1479,7 +1479,12 @@ public abstract class PlayerList {
+ 
+     public PlayerAdvancements getPlayerAdvancements(ServerPlayer player) {
+         UUID uuid = player.getUUID();
+-        PlayerAdvancements advancementdataplayer = (PlayerAdvancements) player.getAdvancements(); // CraftBukkit
++        // Paper start
++        return this.getPlayerAdvancements(uuid, player);
++    }
++    public PlayerAdvancements getPlayerAdvancements(UUID uuid, @Nullable ServerPlayer player) {
++        PlayerAdvancements advancementdataplayer = player == null ? null : player.getAdvancements(); // CraftBukkit
++        // Paper end
+ 
+         if (advancementdataplayer == null) {
+             File file = this.server.getWorldPath(LevelResource.PLAYER_ADVANCEMENTS_DIR).toFile();
+diff --git a/src/main/java/org/bukkit/craftbukkit/CraftOfflinePlayer.java b/src/main/java/org/bukkit/craftbukkit/CraftOfflinePlayer.java
+index 6d2ba650f53de8a460857f1846401a20b50cc43c..37edc2ffe83b26029695f52be4173df884e14ce0 100644
+--- a/src/main/java/org/bukkit/craftbukkit/CraftOfflinePlayer.java
++++ b/src/main/java/org/bukkit/craftbukkit/CraftOfflinePlayer.java
+@@ -304,6 +304,30 @@ public class CraftOfflinePlayer implements OfflinePlayer, ConfigurationSerializa
+ 
+         return result;
+     }
++
++    @Override
++    public org.bukkit.advancement.AdvancementProgress getAdvancementProgress(org.bukkit.advancement.Advancement advancement) {
++        Player player = this.getPlayer();
++        if (player != null) return player.getAdvancementProgress(advancement);
++        com.google.common.base.Preconditions.checkArgument(advancement != null, "advancement");
++
++        org.bukkit.craftbukkit.advancement.CraftAdvancement craft = (org.bukkit.craftbukkit.advancement.CraftAdvancement) advancement;
++        net.minecraft.server.PlayerAdvancements data = this.server.getHandle().getPlayerAdvancements(this.getUniqueId(), null);
++        net.minecraft.advancements.AdvancementProgress progress = data.getOrStartProgress(craft.getHandle());
++        return new org.bukkit.craftbukkit.advancement.CraftAdvancementProgress(craft, data, progress) {
++            @Override
++            public boolean awardCriteria(String criteria) {
++                throw new UnsupportedOperationException("Cannot award criteria to an offline player");
++            }
++
++            @Override
++            public boolean revokeCriteria(String criteria) {
++                boolean result = super.revokeCriteria(criteria);
++                data.save();
++                return result;
++            }
++        };
++    }
+     // Paper end
+ 
+     @Override