--- a/net/minecraft/network/protocol/game/ClientboundSectionBlocksUpdatePacket.java
+++ b/net/minecraft/network/protocol/game/ClientboundSectionBlocksUpdatePacket.java
@@ -30,10 +_,25 @@
 
         for (short s : positions) {
             this.positions[i] = s;
-            this.states[i] = section.getBlockState(SectionPos.sectionRelativeX(s), SectionPos.sectionRelativeY(s), SectionPos.sectionRelativeZ(s));
+            this.states[i] = (section != null) ? section.getBlockState(SectionPos.sectionRelativeX(s), SectionPos.sectionRelativeY(s), SectionPos.sectionRelativeZ(s)) : net.minecraft.world.level.block.Blocks.AIR.defaultBlockState(); // CraftBukkit - SPIGOT-6076, Mojang bug when empty chunk section notified
             i++;
         }
     }
+    // CraftBukkit start - Add constructor
+    public ClientboundSectionBlocksUpdatePacket(SectionPos sectionposition, ShortSet shortset, BlockState[] states) {
+        this.sectionPos = sectionposition;
+        this.positions = shortset.toShortArray();
+        this.states = states;
+    }
+    // CraftBukkit end
+    // Paper start - Multi Block Change API
+    public ClientboundSectionBlocksUpdatePacket(SectionPos sectionPos, it.unimi.dsi.fastutil.shorts.Short2ObjectMap<BlockState> blockChanges) {
+        this.sectionPos = sectionPos;
+        this.positions = blockChanges.keySet().toShortArray();
+        this.states = blockChanges.values().toArray(new BlockState[0]);
+    }
+    // Paper end - Multi Block Change API
+
 
     private ClientboundSectionBlocksUpdatePacket(FriendlyByteBuf buffer) {
         this.sectionPos = SectionPos.of(buffer.readLong());
