diff --git a/Makefile b/Makefile
index bad326820..636cc1d99 100644
--- a/Makefile
+++ b/Makefile
@@ -22,13 +22,16 @@ INCLUDES  := src lib_standalone lib/ArduinoJson/src lib/uuid-common/src lib/uuid
 LIBRARIES := 
 
 CPPCHECK = cppcheck
-CHECKFLAGS = -q --force --std=c++17
+# CHECKFLAGS = -q --force --std=c++17
+CHECKFLAGS = -q --force --std=c++11
 
 #----------------------------------------------------------------------
 # Languages Standard
 #----------------------------------------------------------------------
-C_STANDARD   := -std=c17
-CXX_STANDARD := -std=c++17
+# C_STANDARD   := -std=c17
+# CXX_STANDARD := -std=c++17
+C_STANDARD   := -std=c11
+CXX_STANDARD := -std=c++11
 
 #----------------------------------------------------------------------
 # Defined Symbols
diff --git a/lib/semver/version.inl b/lib/semver/version.inl
index 1ace6abdd..8de18af61 100644
--- a/lib/semver/version.inl
+++ b/lib/semver/version.inl
@@ -90,13 +90,13 @@ int Basic_version<Parser, Comparator>::patch() const {
 template <typename Parser, typename Comparator>
 const std::string Basic_version<Parser, Comparator>::prerelease() const {
     std::string ss;
-    return splice(ss, ver_.prerelease_ids, ".", [](const auto & id) { return id.first; });
+    return splice(ss, ver_.prerelease_ids, ".", [](const Prerelease_identifier & id) { return id.first; });
 }
 
 template <typename Parser, typename Comparator>
 const std::string Basic_version<Parser, Comparator>::build() const {
     std::string ss;
-    return splice(ss, ver_.build_ids, ".", [](const auto & id) { return id; });
+    return splice(ss, ver_.build_ids, ".", [](const std::string & id) { return id; });
 }
 
 template <typename Parser, typename Comparator>
diff --git a/platformio.ini b/platformio.ini
index 25d185268..987ca1252 100644
--- a/platformio.ini
+++ b/platformio.ini
@@ -16,10 +16,10 @@ core_build_flags =
   -D NDEBUG
   -D ARDUINO_ARCH_ESP32=1
   -D ESP32=1
-  -std=gnu++17 -Os
+  ; -Os
 
-core_unbuild_flags = -std=gnu++11 
-; core_unbuild_flags = 
+; core_unbuild_flags = -std=gnu++11 
+core_unbuild_flags = 
 
 ; my_build_flags is set in pio_local.ini
 my_build_flags =
@@ -68,8 +68,6 @@ extra_scripts =
   scripts/rename_fw.py
 board = esp32dev
 platform = espressif32
-; platform_packages =
-; 	framework-arduinoespressif32@3.20005.220925
 board_upload.flash_size = 4MB
 board_build.partitions = esp32_partition_4M.csv
 build_flags = ${common.build_flags}