diff --git a/extern/cloop/src/cloop/Generator.cpp b/extern/cloop/src/cloop/Generator.cpp
index 3cfdd2311fb..5a3ca56f65e 100644
--- a/extern/cloop/src/cloop/Generator.cpp
+++ b/extern/cloop/src/cloop/Generator.cpp
@@ -191,7 +191,9 @@ void CppGenerator::generate()
 	fprintf(out, "#endif\n\n\n");
 
 	fprintf(out, "#ifndef CLOOP_CONSTEXPR\n");
-	fprintf(out, "#if __cplusplus >= 201103L\n");
+	fprintf(out, "#if __cplusplus >= 201703L\n");
+	fprintf(out, "#define CLOOP_CONSTEXPR inline constexpr\n");
+	fprintf(out, "#elif __cplusplus >= 201103L\n");
 	fprintf(out, "#define CLOOP_CONSTEXPR constexpr\n");
 	fprintf(out, "#else\n");
 	fprintf(out, "#define CLOOP_CONSTEXPR const\n");
diff --git a/extern/cloop/src/cloop/cloop.vcxproj b/extern/cloop/src/cloop/cloop.vcxproj
index eee16a54c39..8e72817dcae 100644
--- a/extern/cloop/src/cloop/cloop.vcxproj
+++ b/extern/cloop/src/cloop/cloop.vcxproj
@@ -119,6 +119,8 @@
       <WarningLevel>Level3</WarningLevel>
       <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
       <Optimization>Disabled</Optimization>
+      <LanguageStandard>stdcpp17</LanguageStandard>
+      <AdditionalOptions>/Zc:__cplusplus %(AdditionalOptions)</AdditionalOptions>
     </ClCompile>
     <Link>
       <GenerateDebugInformation>true</GenerateDebugInformation>
@@ -146,6 +148,8 @@
       <RuntimeLibrary>MultiThreadedDLL</RuntimeLibrary>
       <WarningLevel>Level3</WarningLevel>
       <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
+      <LanguageStandard>stdcpp17</LanguageStandard>
+      <AdditionalOptions>/Zc:__cplusplus %(AdditionalOptions)</AdditionalOptions>
     </ClCompile>
     <Link>
       <GenerateDebugInformation>true</GenerateDebugInformation>
@@ -171,4 +175,4 @@
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
   <ImportGroup Label="ExtensionTargets">
   </ImportGroup>
-</Project>
+</Project>
\ No newline at end of file
diff --git a/extern/cloop/src/tests/test1/test1-cpp-dll.vcxproj b/extern/cloop/src/tests/test1/test1-cpp-dll.vcxproj
index 03acdd5900a..c5a24cab979 100644
--- a/extern/cloop/src/tests/test1/test1-cpp-dll.vcxproj
+++ b/extern/cloop/src/tests/test1/test1-cpp-dll.vcxproj
@@ -129,6 +129,8 @@
       <WarningLevel>Level3</WarningLevel>
       <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
       <Optimization>Disabled</Optimization>
+      <AdditionalOptions>/Zc:__cplusplus %(AdditionalOptions)</AdditionalOptions>
+      <LanguageStandard>stdcpp17</LanguageStandard>
     </ClCompile>
     <Link>
       <GenerateDebugInformation>true</GenerateDebugInformation>
@@ -158,6 +160,8 @@
       <RuntimeLibrary>MultiThreadedDLL</RuntimeLibrary>
       <WarningLevel>Level3</WarningLevel>
       <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
+      <AdditionalOptions>/Zc:__cplusplus %(AdditionalOptions)</AdditionalOptions>
+      <LanguageStandard>stdcpp17</LanguageStandard>
     </ClCompile>
     <Link>
       <GenerateDebugInformation>true</GenerateDebugInformation>
@@ -176,4 +180,4 @@
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
   <ImportGroup Label="ExtensionTargets">
   </ImportGroup>
-</Project>
+</Project>
\ No newline at end of file
diff --git a/extern/cloop/src/tests/test1/test1-cpp-exe.vcxproj b/extern/cloop/src/tests/test1/test1-cpp-exe.vcxproj
index 8aed4d0a303..26ead73b5ac 100644
--- a/extern/cloop/src/tests/test1/test1-cpp-exe.vcxproj
+++ b/extern/cloop/src/tests/test1/test1-cpp-exe.vcxproj
@@ -129,6 +129,8 @@
       <WarningLevel>Level3</WarningLevel>
       <Optimization>Disabled</Optimization>
       <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <AdditionalOptions>/Zc:__cplusplus %(AdditionalOptions)</AdditionalOptions>
+      <LanguageStandard>stdcpp17</LanguageStandard>
     </ClCompile>
     <Link>
       <SubSystem>Console</SubSystem>
@@ -161,6 +163,8 @@
       <FunctionLevelLinking>true</FunctionLevelLinking>
       <IntrinsicFunctions>true</IntrinsicFunctions>
       <PreprocessorDefinitions>WIN32;NDEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <AdditionalOptions>/Zc:__cplusplus %(AdditionalOptions)</AdditionalOptions>
+      <LanguageStandard>stdcpp17</LanguageStandard>
     </ClCompile>
     <Link>
       <SubSystem>Console</SubSystem>
@@ -178,4 +182,4 @@
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
   <ImportGroup Label="ExtensionTargets">
   </ImportGroup>
-</Project>
+</Project>
\ No newline at end of file
diff --git a/src/include/firebird/IdlFbInterfaces.h b/src/include/firebird/IdlFbInterfaces.h
index 3033b9cff67..0da59e7f052 100644
--- a/src/include/firebird/IdlFbInterfaces.h
+++ b/src/include/firebird/IdlFbInterfaces.h
@@ -17,7 +17,9 @@
 
 
 #ifndef CLOOP_CONSTEXPR
-#if __cplusplus >= 201103L
+#if __cplusplus >= 201703L
+#define CLOOP_CONSTEXPR inline constexpr
+#elif __cplusplus >= 201103L
 #define CLOOP_CONSTEXPR constexpr
 #else
 #define CLOOP_CONSTEXPR const