diff --git a/command/rakp12.hpp b/command/rakp12.hpp
index f68ec47..2d86bdb 100644
--- a/command/rakp12.hpp
+++ b/command/rakp12.hpp
@@ -65,7 +65,7 @@
  *
  * @return Response data for the command
  */
-std::vector<uint8_t> RAKP12(std::vector<uint8_t>& inPayload,
+std::vector<uint8_t> RAKP12(const std::vector<uint8_t>& inPayload,
                             const message::Handler& handler);
 
 } // namespace command