diff --git a/src/main/java/net/fabricmc/loom/LoomGradlePlugin.java b/src/main/java/net/fabricmc/loom/LoomGradlePlugin.java
index 0690ebf..a4bc030 100644
--- a/src/main/java/net/fabricmc/loom/LoomGradlePlugin.java
+++ b/src/main/java/net/fabricmc/loom/LoomGradlePlugin.java
@@ -25,13 +25,9 @@
 package net.fabricmc.loom;
 
 import net.fabricmc.loom.providers.MappingsProvider;
-import net.fabricmc.loom.providers.MinecraftAssetsProvider;
 import net.fabricmc.loom.providers.MinecraftLibraryProvider;
 import net.fabricmc.loom.task.*;
 import net.fabricmc.loom.task.fernflower.FernFlowerTask;
-import net.fabricmc.loom.util.LineNumberRemapper;
-import net.fabricmc.loom.util.progress.ProgressLogger;
-import net.fabricmc.stitch.util.StitchUtil;
 import org.gradle.api.Project;
 import org.gradle.api.Task;
 import org.gradle.api.tasks.TaskContainer;
@@ -64,7 +60,7 @@ public class LoomGradlePlugin extends AbstractPlugin {
 		tasks.register("cleanLoomBinaries", CleanLoomBinaries.class);
 		tasks.register("cleanLoomMappings", CleanLoomMappings.class);
 
-		tasks.register("updateMappings", UpdateMappingsTask.class, t -> {
+		tasks.register("migrateMappings", MigrateMappingsTask.class, t -> {
 			t.getOutputs().upToDateWhen((o) -> false);
 		});
 
diff --git a/src/main/java/net/fabricmc/loom/providers/MappingsProvider.java b/src/main/java/net/fabricmc/loom/providers/MappingsProvider.java
index 1eac733..6f43f56 100644
--- a/src/main/java/net/fabricmc/loom/providers/MappingsProvider.java
+++ b/src/main/java/net/fabricmc/loom/providers/MappingsProvider.java
@@ -51,7 +51,7 @@ public class MappingsProvider extends DependencyProvider {
 	public String minecraftVersion;
 	public String mappingsVersion;
 
-	private File MAPPINGS_DIR;
+	public File MAPPINGS_DIR;
 	public File MAPPINGS_TINY_BASE;
 	public File MAPPINGS_TINY;
 	public File MAPPINGS_MIXIN_EXPORT;
diff --git a/src/main/java/net/fabricmc/loom/task/UpdateMappingsTask.java b/src/main/java/net/fabricmc/loom/task/MigrateMappingsTask.java
similarity index 75%
rename from src/main/java/net/fabricmc/loom/task/UpdateMappingsTask.java
rename to src/main/java/net/fabricmc/loom/task/MigrateMappingsTask.java
index b52309a..2721084 100644
--- a/src/main/java/net/fabricmc/loom/task/UpdateMappingsTask.java
+++ b/src/main/java/net/fabricmc/loom/task/MigrateMappingsTask.java
@@ -26,6 +26,7 @@ package net.fabricmc.loom.task;
 
 import net.fabricmc.loom.LoomGradleExtension;
 import net.fabricmc.loom.util.Constants;
+import net.fabricmc.loom.util.Version;
 import net.fabricmc.mappings.*;
 import org.cadixdev.lorenz.MappingSet;
 import org.cadixdev.lorenz.io.MappingsReader;
@@ -40,17 +41,54 @@ import java.io.IOException;
 import java.util.HashMap;
 import java.util.Map;
 
-public class UpdateMappingsTask extends AbstractLoomTask {
+public class MigrateMappingsTask extends AbstractLoomTask {
     @TaskAction
     public void doTask() throws Throwable {
         Project project = getProject();
         LoomGradleExtension extension = project.getExtensions().getByType(LoomGradleExtension.class);
+        Map<String, ?> properties = project.getProperties();
 
         project.getLogger().lifecycle(":loading mappings");
 
-        File mappingsFile = new File((String) project.getProperties().get("targetMappingsFile"));
-        File inputDir = new File((String) project.getProperties().get("inputDir"));
-        File outputDir = new File((String) project.getProperties().get("outputDir"));
+        File mappingsFile = null;
+
+        if (properties.containsKey("targetMappingsFile")) {
+            mappingsFile = new File((String) properties.get("targetMappingsFile"));
+        } else if (properties.containsKey("targetMappingsArtifact")) {
+            String[] artifactName = ((String) properties.get("targetMappingsArtifact")).split(":");
+            if (artifactName.length != 3) {
+                throw new RuntimeException("Invalid artifact name: " + properties.get("targetMappingsArtifact"));
+            }
+
+            String mappingsName = artifactName[0] + "." + artifactName[1];
+
+            Version v = new Version(artifactName[2]);
+            String minecraftVersion = v.getMinecraftVersion();
+            String mappingsVersion = v.getMappingsVersion();
+
+            mappingsFile = new File(extension.getMappingsProvider().MAPPINGS_DIR, mappingsName + "-tiny-" + minecraftVersion + "-" + mappingsVersion);
+        }
+
+        if (mappingsFile == null || !mappingsFile.exists()) {
+            throw new RuntimeException("Could not find mappings file: " + (mappingsFile != null ? mappingsFile : "null"));
+        }
+
+        if (!properties.containsKey("inputDir") || !properties.containsKey("outputDir")) {
+            throw new RuntimeException("Must specify input and output dir!");
+        }
+
+        File inputDir = new File((String) properties.get("inputDir"));
+        File outputDir = new File((String) properties.get("outputDir"));
+
+        if (!inputDir.exists() || !inputDir.isDirectory()) {
+            throw new RuntimeException("Could not find input directory: " + inputDir);
+        }
+
+        if (!outputDir.exists()) {
+            if (!outputDir.mkdirs()) {
+                throw new RuntimeException("Could not create output directory:"  + outputDir);
+            }
+        }
 
         Mappings sourceMappings = extension.getMappingsProvider().getMappings();
         Mappings targetMappings;