Try at 1.21.1 (broken at the moment)

Author: TrigamDev

build.gradle

@@ -36,7 +36,7 @@ fabricApi {
 
 dependencies {
 	// To change the versions see the gradle.properties file
-	minecraft "com.mojang:minecraft:${project.minecraft_version}"
+	minecraft "com.mojang:minecraft:${stonecutter.current.version}"
 	mappings "net.fabricmc:yarn:${project.yarn_mappings}:v2"
 	modImplementation "net.fabricmc:fabric-loader:${project.loader_version}"
 
@@ -49,9 +49,11 @@ dependencies {
 
 processResources {
 	inputs.property "version", project.version
+	inputs.property "minecraft", stonecutter.current.version
 
 	filesMatching("fabric.mod.json") {
 		expand "version": project.version
+		expand "minecraft": stonecutter.current.version
 	}
 }
 

settings.gradle

@@ -15,7 +15,7 @@ plugins {
 
 stonecutter {
 	create( rootProject ) {
-		versions "1.21.4"
+		versions "1.21.4", "1.21.1"
 		vcsVersion = "1.21.4"
 	}
 }

versions/1.21.1/gradle.properties

@@ -0,0 +1,3 @@
+minecraft_version=1.21.1
+yarn_mappings=1.21.1+build.3
+fabric_version=0.115.3+1.21.1

versions/1.21.1/src/main/resources/field.accesswidener

@@ -0,0 +1,3 @@
+accessWidener v2 named
+
+accessible method net/minecraft/client/render/block/entity/BannerBlockEntityRenderer render (Lnet/minecraft/client/util/math/MatrixStack;Lnet/minecraft/client/render/VertexConsumerProvider;IIFLnet/minecraft/client/render/block/entity/model/BannerBlockModel;Lnet/minecraft/client/render/block/entity/model/BannerFlagBlockModel;FLnet/minecraft/util/DyeColor;Lnet/minecraft/component/type/BannerPatternsComponent;)V

versions/1.21.4/gradle.properties

@@ -1,3 +1,3 @@
 minecraft_version=1.21.4
-yarn_mappings=1.21.4+build.1
-fabric_version=0.110.5+1.21.4
+yarn_mappings=1.21.4+build.8
+fabric_version=0.119.2+1.21.4