diff --git a/common/hardware_interface.h b/common/hardware_interface.h
index 4f0305f..0fffbfb 100644
--- a/common/hardware_interface.h
+++ b/common/hardware_interface.h
@@ -142,6 +142,19 @@
   // If |warm_reset| is true, sets the warm reset to indicate a warm reset is
   // needed on the next reboot. Otherwise, clears the flag.
   virtual void SetWarmReset(bool warm_reset) = 0;
+
+  // Return the version/timestamp for partition `partition_name`.
+  // Don't make any assumption about the formatting of returned string.
+  // Only used for logging/debugging purposes.
+  virtual std::string GetVersionForLogging(
+      const std::string& partition_name) const = 0;
+
+  // Return true if and only if `new_version` is "newer" than the
+  // version number of partition `partition_name`. The notion of
+  // "newer" is defined by this function. Caller should not make
+  // any assumption about the underlying logic.
+  virtual bool IsPartitionUpdateValid(const std::string& partition_name,
+                                      const std::string& new_version) const = 0;
 };
 
 }  // namespace chromeos_update_engine