untested 1.21.1 port

build.gradle

@@ -32,7 +32,7 @@ repositories {
 dependencies {
 	// To change the versions see the gradle.properties file
 	minecraft "com.mojang:minecraft:${project.minecraft_version}"
-	mappings "org.quiltmc:quilt-mappings:${project.yarn_mappings}:intermediary-v2"
+	mappings "org.quiltmc:quilt-mappings:${project.quilt_mappings}:intermediary-v2"
 	modImplementation "net.fabricmc:fabric-loader:${project.loader_version}"
 
 	// Fabric API. This is technically optional, but you probably want it anyway.

gradle.properties

@@ -4,14 +4,14 @@ org.gradle.parallel=true
 
 # Fabric Properties
 # check these on https://fabricmc.net/develop
-minecraft_version=1.20.1
-yarn_mappings=1.20.1+build.10
-loader_version=0.16.9
+minecraft_version=1.21.1
+quilt_mappings=1.21.1+build.9
+loader_version=0.16.10
 
 # Mod Properties
-mod_version=4.0.0+mc1.20.1
+mod_version=4.0.0+mc1.21.1
 maven_group=gay.debuggy
 archives_base_name=architecture_extensions
 
 # Dependencies
-fabric_version=0.92.3+1.20.1
+fabric_version=0.114.0+1.21.1

src/main/java/gay/debuggy/architecture_extensions/ArchExItemGroups.java

@@ -14,7 +14,7 @@
 
 public class ArchExItemGroups {
 	public static RegistryKey<ItemGroup> makeItemGroupKey(String mod_id, String itemGroupPath) {
-		return RegistryKey.of(Registries.ITEM_GROUP.getKey(), new Identifier(mod_id, itemGroupPath));
+		return RegistryKey.of(Registries.ITEM_GROUP.getKey(), Identifier.of(mod_id, itemGroupPath));
 	}
 
 	public static final RegistryKey<ItemGroup> ARCH_EX_JSON_BLOCKS_KEY = makeItemGroupKey(MOD_ID, "json_blocks");

src/main/java/gay/debuggy/architecture_extensions/ArchitectureExtensionsBlocks.java

@@ -12,12 +12,12 @@
 
 public class ArchitectureExtensionsBlocks {
 	private static <T extends Block> T registerBlock(String path, T block) {
-		Registry.register(Registries.BLOCK, new Identifier(ArchitectureExtensions.MOD_ID, path), block);
-		Registry.register(Registries.ITEM, new Identifier(ArchitectureExtensions.MOD_ID, path), new BlockItem(block, new Item.Settings()));
+		Registry.register(Registries.BLOCK, Identifier.of(ArchitectureExtensions.MOD_ID, path), block);
+		Registry.register(Registries.ITEM, Identifier.of(ArchitectureExtensions.MOD_ID, path), new BlockItem(block, new Item.Settings()));
 		return block;
 	}
 
-	public static final BeamBlock BIRCH_BEAM = registerBlock("birch_beam", new BeamBlock(FabricBlockSettings.copyOf(Blocks.BIRCH_LOG)));
+	public static final BeamBlock BIRCH_BEAM = registerBlock("birch_beam", new BeamBlock(Block.Settings.copy(Blocks.BIRCH_LOG)));
 
 	public static void init() {}
 }

src/main/resources/fabric.mod.json

@@ -26,7 +26,7 @@
 	"mixins": [],
 	"depends": {
 		"fabricloader": ">=0.16.9",
-		"minecraft": ["1.20", "1.20.1"],
+		"minecraft": ["1.21.1"],
 		"java": ">=17",
 		"fabric-api": "*"
 	}