diff --git a/common/dlcservice_interface.h b/common/dlcservice_interface.h
index aa24105..3524d50 100644
--- a/common/dlcservice_interface.h
+++ b/common/dlcservice_interface.h
@@ -34,6 +34,14 @@
   // On failure it returns false.
   virtual bool GetInstalled(std::vector<std::string>* dlc_module_ids) = 0;
 
+  // Returns true if dlcservice successfully handled the install completion
+  // method call, otherwise false.
+  virtual bool InstallCompleted(const std::vector<std::string>& ids) = 0;
+
+  // Returns true if dlcservice successfully handled the update completion
+  // method call, otherwise false.
+  virtual bool UpdateCompleted(const std::vector<std::string>& ids) = 0;
+
  protected:
   DlcServiceInterface() = default;