diff --git a/command/rakp34.hpp b/command/rakp34.hpp
index e3d82ff..a110a24 100644
--- a/command/rakp34.hpp
+++ b/command/rakp34.hpp
@@ -50,7 +50,7 @@
  *
  * @return Response data for the command
  */
-std::vector<uint8_t> RAKP34(std::vector<uint8_t>& inPayload,
+std::vector<uint8_t> RAKP34(const std::vector<uint8_t>& inPayload,
                             const message::Handler& handler);
 
 } // namespace command