diff --git a/build.gradle b/build.gradle
index d654f8e..3eeff4c 100644
--- a/build.gradle
+++ b/build.gradle
@@ -82,7 +82,7 @@ dependencies {
 	implementation 'net.fabricmc:access-widener:2.0.0'
 	implementation 'net.fabricmc:mapping-io:0.2.1'
 
-	implementation ('net.fabricmc:lorenz-tiny:4.0.1') {
+	implementation ('net.fabricmc:lorenz-tiny:4.0.2') {
 		transitive = false
 	}
 
diff --git a/src/test/groovy/net/fabricmc/loom/test/LoomTestConstants.groovy b/src/test/groovy/net/fabricmc/loom/test/LoomTestConstants.groovy
index a82e908..bb1a2ce 100644
--- a/src/test/groovy/net/fabricmc/loom/test/LoomTestConstants.groovy
+++ b/src/test/groovy/net/fabricmc/loom/test/LoomTestConstants.groovy
@@ -26,7 +26,7 @@ package net.fabricmc.loom.test
 
 class LoomTestConstants {
     public final static String DEFAULT_GRADLE = "7.0.1"
-    public final static String PRE_RELEASE_GRADLE = "7.4-20210927222644+0000"
+    public final static String PRE_RELEASE_GRADLE = "7.4-20210929223033+0000"
 
     public final static String[] STANDARD_TEST_VERSIONS = [DEFAULT_GRADLE, PRE_RELEASE_GRADLE]
 }
diff --git a/src/test/groovy/net/fabricmc/loom/test/integration/MigrateMappingsTest.groovy b/src/test/groovy/net/fabricmc/loom/test/integration/MigrateMappingsTest.groovy
new file mode 100644
index 0000000..e53f931
--- /dev/null
+++ b/src/test/groovy/net/fabricmc/loom/test/integration/MigrateMappingsTest.groovy
@@ -0,0 +1,50 @@
+/*
+ * This file is part of fabric-loom, licensed under the MIT License (MIT).
+ *
+ * Copyright (c) 2021 FabricMC
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package net.fabricmc.loom.test.integration
+
+import net.fabricmc.loom.test.util.GradleProjectTestTrait
+import spock.lang.Specification
+import spock.lang.Unroll
+
+import static net.fabricmc.loom.test.LoomTestConstants.STANDARD_TEST_VERSIONS
+import static org.gradle.testkit.runner.TaskOutcome.SUCCESS
+
+class MigrateMappingsTest extends Specification implements GradleProjectTestTrait {
+    @Unroll
+    def "Migrate mappings (gradle #version)"() {
+        setup:
+            def gradle = gradleProject(project: "java16", version: version)
+
+        when:
+            def result = gradle.run(tasks: ["migrateMappings", "--mappings", "21w38a+build.10"])
+
+        then:
+            result.task(":migrateMappings").outcome == SUCCESS
+            // TODO check it actually did something
+
+        where:
+            version << STANDARD_TEST_VERSIONS
+    }
+}