diff --git a/flash.hpp b/flash.hpp
index 470d99c..5069680 100644
--- a/flash.hpp
+++ b/flash.hpp
@@ -22,6 +22,11 @@
      * @brief Writes the image file(s) to flash
      */
     virtual void flashWrite() = 0;
+
+    /**
+     * @brief Takes action when the state of the activation service file changes
+     */
+    virtual void onStateChanges(sdbusplus::message::message& msg) = 0;
 };
 
 } // namespace updater