diff --git a/gradle-plugin/src/main/kotlin/xyz/wagyourtail/jvmdg/gradle/task/DowngradeJar.kt b/gradle-plugin/src/main/kotlin/xyz/wagyourtail/jvmdg/gradle/task/DowngradeJar.kt
index de0c02ee..d2affdb7 100644
--- a/gradle-plugin/src/main/kotlin/xyz/wagyourtail/jvmdg/gradle/task/DowngradeJar.kt
+++ b/gradle-plugin/src/main/kotlin/xyz/wagyourtail/jvmdg/gradle/task/DowngradeJar.kt
@@ -56,7 +56,7 @@ abstract class DowngradeJar : Jar(), DowngradeFlags {
             )
         }
 
-        inputFile.asFile.get().toPath().readZipInputStreamFor("META-INF/MANIFEST.MF", false) { inp ->
+        tempOutput.toPath().readZipInputStreamFor("META-INF/MANIFEST.MF", false) { inp ->
             // write to temp file
             val inpTmp = temporaryDir.toPath().resolve("input-manifest.MF")
             inpTmp.outputStream(StandardOpenOption.CREATE, StandardOpenOption.TRUNCATE_EXISTING).use { out ->
diff --git a/src/main/java/xyz/wagyourtail/jvmdg/cli/Flags.java b/src/main/java/xyz/wagyourtail/jvmdg/cli/Flags.java
index 3206ea32..62c1a275 100644
--- a/src/main/java/xyz/wagyourtail/jvmdg/cli/Flags.java
+++ b/src/main/java/xyz/wagyourtail/jvmdg/cli/Flags.java
@@ -18,6 +18,8 @@
 import java.util.Set;
 
 public class Flags {
+    public static final String jvmdgVersion = Flags.class.getPackage().getImplementationVersion();
+
     public int classVersion = Opcodes.V1_8;
     public File api = null;
     public boolean quiet = Boolean.getBoolean(Constants.QUIET);
diff --git a/src/main/java/xyz/wagyourtail/jvmdg/compile/PathDowngrader.java b/src/main/java/xyz/wagyourtail/jvmdg/compile/PathDowngrader.java
index bf7a58af..0b139e6a 100644
--- a/src/main/java/xyz/wagyourtail/jvmdg/compile/PathDowngrader.java
+++ b/src/main/java/xyz/wagyourtail/jvmdg/compile/PathDowngrader.java
@@ -1,11 +1,13 @@
 package xyz.wagyourtail.jvmdg.compile;
 
 import xyz.wagyourtail.jvmdg.ClassDowngrader;
+import xyz.wagyourtail.jvmdg.cli.Flags;
 import xyz.wagyourtail.jvmdg.util.*;
 
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
+import java.io.OutputStream;
 import java.lang.instrument.IllegalClassFormatException;
 import java.net.URL;
 import java.net.URLClassLoader;
@@ -16,6 +18,8 @@
 import java.util.*;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.atomic.AtomicReference;
+import java.util.jar.Attributes;
+import java.util.jar.Manifest;
 
 public class PathDowngrader {
 
@@ -118,6 +122,17 @@ public byte[] apply(String s) {
                                     throw new IOException("Failed to downgrade " + path, e);
                                 }
                             }
+                        } else if (path.toString().equals("META-INF/MANIFEST.MF")) {
+                            // add version number to manifest
+                            try(InputStream is = Files.newInputStream(path)) {
+                                Manifest manifest = new Manifest(is);
+                                Attributes attr = manifest.getMainAttributes();
+                                attr.put("JvmDowngrader-Version", Flags.jvmdgVersion);
+
+                                try (OutputStream os = Files.newOutputStream(outFile, StandardOpenOption.CREATE, StandardOpenOption.TRUNCATE_EXISTING)) {
+                                    manifest.write(os);
+                                }
+                            }
                         } else {
                             // strip signatures since downgraded classes will not have the same signatures
                             if (path.toString().startsWith("META-INF/") && (path.toString().endsWith(".SF") || path.toString().endsWith(".DSA") || path.toString().endsWith(".RSA"))) {