--- libjson-rpc-cpp-1.3.0/src/jsonrpccpp/server/connectors/httpserver.cpp.orig	2020-08-20 15:21:21.993000000 +0200
+++ libjson-rpc-cpp-1.3.0/src/jsonrpccpp/server/connectors/httpserver.cpp	2020-08-20 15:24:49.158000000 +0200
@@ -151,7 +151,7 @@
   this->SetHandler(NULL);
 }
 
-int HttpServer::callback(void *cls, MHD_Connection *connection, const char *url,
+MHD_Result HttpServer::callback(void *cls, MHD_Connection *connection, const char *url,
                          const char *method, const char *version,
                          const char *upload_data, size_t *upload_data_size,
                          void **con_cls) {
--- libjson-rpc-cpp-1.3.0/src/jsonrpccpp/server/connectors/httpserver.h.orig	2020-08-20 15:22:10.705000000 +0200
+++ libjson-rpc-cpp-1.3.0/src/jsonrpccpp/server/connectors/httpserver.h	2020-08-20 15:24:04.849000000 +0200
@@ -79,7 +79,7 @@
   std::map<std::string, IClientConnectionHandler *> urlhandler;
   struct sockaddr_in loopback_addr;
 
-  static int callback(void *cls, struct MHD_Connection *connection,
+  static MHD_Result callback(void *cls, struct MHD_Connection *connection,
                       const char *url, const char *method, const char *version,
                       const char *upload_data, size_t *upload_data_size,
                       void **con_cls);