diff --git a/edify/include/edify/updater_interface.h b/edify/include/edify/updater_interface.h
index a4d581e..aa977e3 100644
--- a/edify/include/edify/updater_interface.h
+++ b/edify/include/edify/updater_interface.h
@@ -44,4 +44,5 @@
   virtual ZipArchiveHandle GetPackageHandle() const = 0;
   virtual std::string GetResult() const = 0;
   virtual uint8_t* GetMappedPackageAddress() const = 0;
+  virtual size_t GetMappedPackageLength() const = 0;
 };
diff --git a/updater/include/updater/updater.h b/updater/include/updater/updater.h
index 08816bf..8676b60 100644
--- a/updater/include/updater/updater.h
+++ b/updater/include/updater/updater.h
@@ -62,10 +62,12 @@
   std::string GetResult() const override {
     return result_;
   }
-
   uint8_t* GetMappedPackageAddress() const override {
     return mapped_package_.addr;
   }
+  size_t GetMappedPackageLength() const override {
+    return mapped_package_.length;
+  }
 
  private:
   friend class UpdaterTestBase;