diff --git a/src/rpc/mining.cpp b/src/rpc/mining.cpp
index 1b923da34d..5de6759943 100644
--- a/src/rpc/mining.cpp
+++ b/src/rpc/mining.cpp
@@ -1017,7 +1017,7 @@ UniValue getnewblockhex(const JSONRPCRequest& request)
                             },
                         },
                         "proposed_parameters"},
-                        {"commit_data", RPCArg::Type::STR_HEX, RPCArg::Optional::NO, "Data in hex to be committed to in an additional coinbase output."},
+                        {"commit_data", RPCArg::Type::STR_HEX, RPCArg::Optional::OMITTED_NAMED_ARG, "Data in hex to be committed to in an additional coinbase output."},
                 },
                 RPCResult{
                     "blockhex      (hex) The block hex\n"