diff --git a/mappings/net/minecraft/client/gui/menu/WorkingGui.mapping b/mappings/net/minecraft/client/gui/menu/WorkingGui.mapping
index c2e0cb91f4..d30ec84b35 100644
--- a/mappings/net/minecraft/client/gui/menu/WorkingGui.mapping
+++ b/mappings/net/minecraft/client/gui/menu/WorkingGui.mapping
@@ -3,6 +3,8 @@ CLASS crg net/minecraft/client/gui/menu/WorkingGui
 	FIELD f task Ljava/lang/String;
 	FIELD g progress I
 	FIELD h done Z
+	METHOD a progressStagePercentage (I)V
+		ARG 1 i
 	METHOD a draw (IIF)V
 		ARG 1 mouseX
 		ARG 2 mouseY
diff --git a/mappings/net/minecraft/server/MinecraftServer.mapping b/mappings/net/minecraft/server/MinecraftServer.mapping
index 59a7455855..73e17cf8c8 100644
--- a/mappings/net/minecraft/server/MinecraftServer.mapping
+++ b/mappings/net/minecraft/server/MinecraftServer.mapping
@@ -1,8 +1,9 @@
 CLASS net/minecraft/server/MinecraftServer net/minecraft/server/MinecraftServer
 	CLASS net/minecraft/server/MinecraftServer$1
 		FIELD b lastProgressUpdate J
-		METHOD a (I)V
+		METHOD a progressStagePercentage (I)V
 			ARG 0 percentage
+			ARG 1 i
 	FIELD A spawnAnimals Z
 	FIELD B spawnNpcs Z
 	FIELD C pvpEnabled Z
diff --git a/mappings/net/minecraft/world/biome/BiomeSource.mapping b/mappings/net/minecraft/world/biome/BiomeSource.mapping
new file mode 100644
index 0000000000..738752afc2
--- /dev/null
+++ b/mappings/net/minecraft/world/biome/BiomeSource.mapping
@@ -0,0 +1 @@
+CLASS bbn net/minecraft/world/biome/BiomeSource
diff --git a/mappings/net/minecraft/world/chunk/storage/RegionFile.mapping b/mappings/net/minecraft/world/chunk/storage/RegionFile.mapping
new file mode 100644
index 0000000000..a6bf630925
--- /dev/null
+++ b/mappings/net/minecraft/world/chunk/storage/RegionFile.mapping
@@ -0,0 +1,53 @@
+CLASS bqw net/minecraft/world/chunk/storage/RegionFile
+	CLASS bqw$a ChunkBuffer
+		FIELD b x I
+		FIELD c z I
+		METHOD <init> (Lbqw;II)V
+			ARG 2 x
+			ARG 3 z
+	FIELD a EMPTY_SECTOR [B
+	FIELD b fileName Ljava/io/File;
+	FIELD c file Ljava/io/RandomAccessFile;
+	FIELD d offsets [I
+	FIELD e chunkTimestamps [I
+	FIELD f sectorFree Ljava/util/List;
+	FIELD g sizeDelta I
+	FIELD h lastModified J
+	METHOD <init> (Ljava/io/File;)V
+		ARG 1 fileName
+	METHOD a getChunkDataInputStream (II)Ljava/io/DataInputStream;
+		ARG 1 x
+		ARG 2 z
+	METHOD a setOffset (III)V
+		ARG 1 x
+		ARG 2 z
+		ARG 3 offset
+	METHOD a write (II[BI)V
+		ARG 1 x
+		ARG 2 z
+		ARG 3 data
+		ARG 4 length
+	METHOD a write (I[BI)V
+		ARG 1 sectorNumber
+		ARG 2 data
+		ARG 3 length
+	METHOD b (II)Z
+		ARG 1 x
+		ARG 2 z
+	METHOD b setTimestamp (III)V
+		ARG 1 x
+		ARG 2 z
+		ARG 3 value
+	METHOD c close ()V
+	METHOD c (II)Ljava/io/DataOutputStream;
+		ARG 1 x
+		ARG 2 z
+	METHOD d hasChunk (II)Z
+		ARG 1 x
+		ARG 2 z
+	METHOD e outOfBounds (II)Z
+		ARG 1 x
+		ARG 2 z
+	METHOD f getOffset (II)I
+		ARG 1 x
+		ARG 2 z
diff --git a/mappings/net/minecraft/world/level/storage/AnvilLevelStorage.mapping b/mappings/net/minecraft/world/level/storage/AnvilLevelStorage.mapping
index e86edbb310..f453537889 100644
--- a/mappings/net/minecraft/world/level/storage/AnvilLevelStorage.mapping
+++ b/mappings/net/minecraft/world/level/storage/AnvilLevelStorage.mapping
@@ -1,23 +1,32 @@
 CLASS cfy net/minecraft/world/level/storage/AnvilLevelStorage
 	FIELD e LOGGER Lorg/apache/logging/log4j/Logger;
 	METHOD a getName ()Ljava/lang/String;
-	METHOD a loadRegionFile (Ljava/io/File;Ljava/io/File;Lbbn;IILyn;)V
-		ARG 1 regionDir
-		ARG 2 file
+	METHOD a convertRegion (Ljava/io/File;Ljava/io/File;Lbbn;IILyn;)V
+		ARG 1 baseFolder
+		ARG 2 regionFile
+		ARG 3 biomeSource
 		ARG 4 progressStart
 		ARG 5 progressEnd
-	METHOD a loadRegionFiles (Ljava/io/File;Ljava/lang/Iterable;Lbbn;IILyn;)V
-		ARG 1 regionDir
-		ARG 2 files
-		ARG 4 progressStart
-		ARG 5 progressEnd
-	METHOD a getRegionFiles (Ljava/io/File;Ljava/util/Collection;)V
-		ARG 1 worldDir
+		ARG 6 progress
+	METHOD a convertRegions (Ljava/io/File;Ljava/lang/Iterable;Lbbn;IILyn;)V
+		ARG 1 baseFolder
+		ARG 2 regionFiles
+		ARG 3 biomeSource
+		ARG 4 currentCount
+		ARG 5 totalCount
+		ARG 6 progress
+	METHOD a addRegionFiles (Ljava/io/File;Ljava/util/Collection;)V
+		ARG 1 baseDir
+		ARG 2 regionFiles
 	METHOD a isConvertible (Ljava/lang/String;)Z
-	METHOD a convert (Ljava/lang/String;Lyn;)Z
-		ARG 1 levelName
+		ARG 1 levelId
+	METHOD a convertLevel (Ljava/lang/String;Lyn;)Z
+		ARG 1 levelId
+		ARG 2 progress
 	METHOD b getAvailableLevels ()Ljava/util/List;
 	METHOD b requiresConversion (Ljava/lang/String;)Z
+		ARG 1 levelId
 	METHOD c getVersion ()I
 	METHOD d clearAll ()V
-	METHOD i moveLevelDatBackup (Ljava/lang/String;)V
+	METHOD i makeMcrLevelDatBackup (Ljava/lang/String;)V
+		ARG 1 levelId
diff --git a/mappings/net/minecraft/world/level/storage/LevelStorage.mapping b/mappings/net/minecraft/world/level/storage/LevelStorage.mapping
index fe4f4e3da6..86f3d833d3 100644
--- a/mappings/net/minecraft/world/level/storage/LevelStorage.mapping
+++ b/mappings/net/minecraft/world/level/storage/LevelStorage.mapping
@@ -1,12 +1,15 @@
 CLASS cgg net/minecraft/world/level/storage/LevelStorage
 	METHOD a getName ()Ljava/lang/String;
 	METHOD a isConvertible (Ljava/lang/String;)Z
+		ARG 1 levelId
 	METHOD a rename (Ljava/lang/String;Ljava/lang/String;)V
 		ARG 1 oldLevelName
-	METHOD a convert (Ljava/lang/String;Lyn;)Z
-		ARG 1 levelName
+	METHOD a convertLevel (Ljava/lang/String;Lyn;)Z
+		ARG 1 levelId
+		ARG 2 progress
 	METHOD b getAvailableLevels ()Ljava/util/List;
 	METHOD b requiresConversion (Ljava/lang/String;)Z
+		ARG 1 levelId
 	METHOD b resolveFile (Ljava/lang/String;Ljava/lang/String;)Ljava/io/File;
 		ARG 1 first
 	METHOD c getLevelProperties (Ljava/lang/String;)Lcgd;
diff --git a/mappings/net/minecraft/world/level/storage/OldLevelStorage.mapping b/mappings/net/minecraft/world/level/storage/OldLevelStorage.mapping
index ec664b2ec8..ba7c56cfc5 100644
--- a/mappings/net/minecraft/world/level/storage/OldLevelStorage.mapping
+++ b/mappings/net/minecraft/world/level/storage/OldLevelStorage.mapping
@@ -1,16 +1,19 @@
 CLASS cgc net/minecraft/world/level/storage/OldLevelStorage
-	FIELD a rootPath Ljava/nio/file/Path;
+	FIELD a baseDir Ljava/nio/file/Path;
 	FIELD e LOGGER Lorg/apache/logging/log4j/Logger;
 	METHOD a getName ()Ljava/lang/String;
 	METHOD a isConvertible (Ljava/lang/String;)Z
+		ARG 1 levelId
 	METHOD a rename (Ljava/lang/String;Ljava/lang/String;)V
 		ARG 1 oldLevelName
-	METHOD a convert (Ljava/lang/String;Lyn;)Z
-		ARG 1 levelName
+	METHOD a convertLevel (Ljava/lang/String;Lyn;)Z
+		ARG 1 levelId
+		ARG 2 progress
 	METHOD a deleteRecursive ([Ljava/io/File;)Z
 		ARG 0 files
 	METHOD b getAvailableLevels ()Ljava/util/List;
 	METHOD b requiresConversion (Ljava/lang/String;)Z
+		ARG 1 levelId
 	METHOD b resolveFile (Ljava/lang/String;Ljava/lang/String;)Ljava/io/File;
 		ARG 1 first
 	METHOD c getLevelProperties (Ljava/lang/String;)Lcgd;
diff --git a/mappings/yn.mapping b/mappings/yn.mapping
new file mode 100644
index 0000000000..e90ca37a14
--- /dev/null
+++ b/mappings/yn.mapping
@@ -0,0 +1,3 @@
+CLASS yn
+	METHOD a progressStagePercentage (I)V
+		ARG 1 i