diff -rupN --no-dereference gmsh-4.5.4-source/CMakeLists.txt gmsh-4.5.4-source-new/CMakeLists.txt
--- gmsh-4.5.4-source/CMakeLists.txt	2020-03-02 11:12:53.640187196 +0100
+++ gmsh-4.5.4-source-new/CMakeLists.txt	2020-03-02 11:12:53.642187205 +0100
@@ -44,7 +44,7 @@ opt(BUILD_IOS "Enable iOS library target
 opt(CGNS "Enable CGNS import/export (experimental)" ${DEFAULT})
 opt(CGNS_CPEX0045 "Enable high-order CGNS import/export following CPEX0045 (experimental)" OFF)
 opt(CAIRO "Enable Cairo to render fonts (experimental)" ${DEFAULT})
-opt(CXX11 "Enable C++11" ON)
+opt(CXX14 "Enable C++14" ON)
 opt(C99 "Enable C99" ON)
 opt(PROFILE "Enable profiling compiler flags" OFF)
 opt(DINTEGRATION "Enable discrete integration (needed for levelsets)" ${DEFAULT})
@@ -325,13 +325,13 @@ if(ENABLE_OPENACC)
   endif()
 endif()
 
-if(ENABLE_CXX11)
-  # in recent cmake versions we could do e.g. set(CMAKE_CXX_STANDARD 11)
-  check_cxx_compiler_flag("-std=c++11" STDCXX11)
-  if(STDCXX11)
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
-  endif()
-endif()
+if(ENABLE_CXX14)
+  check_cxx_compiler_flag("-std=c++14" STDCXX14)
+  if(STDCXX14)
+    set_config_option(HAVE_CXX14 "C++14")
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++14")
+  endif(STDCXX14)
+endif(ENABLE_CXX14)
 
 if(ENABLE_C99)
   # in recent cmake versions we could do e.g. set(CMAKE_C_STANDARD 99)
@@ -1536,10 +1536,10 @@ if(ENABLE_REVOROPT)
     get_source_file_property(PROP Plugin/CVTRemesh.cpp COMPILE_FLAGS)
     if(PROP)
       set_source_files_properties(Plugin/CVTRemesh.cpp PROPERTIES
-                                  COMPILE_FLAGS "${PROP} -std=c++11")
+                                  COMPILE_FLAGS "${PROP} -std=c++14")
     else()
       set_source_files_properties(Plugin/CVTRemesh.cpp PROPERTIES
-                                  COMPILE_FLAGS "-std=c++11")
+                                  COMPILE_FLAGS "-std=c++14")
     endif()
   else()
     message(WARNING "Revoropt requires Eigen3, Mesh, Plugins, ANN and ALGLIB")
@@ -1719,7 +1719,7 @@ if(ENABLE_BUILD_ANDROID)
     message(FATAL_ERROR "Cannot compile Gmsh for android without android-cmake")
   endif()
   add_definitions(-D_GLIBCXX_USE_C99_MATH=1)
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++14")
   set(CMAKE_BUILD_TYPE Release)
   set(LIBRARY_OUTPUT_PATH_ROOT ${CMAKE_CURRENT_BINARY_DIR})
   set(LIBRARY_OUTPUT_PATH ${CMAKE_CURRENT_BINARY_DIR}/libs/)