diff --git a/applications/utilities/mesh/conversion/ansysToFoam/ansysToFoam.L b/applications/utilities/mesh/conversion/ansysToFoam/ansysToFoam.L
index fb6cd4557..85c8e4199 100644
--- a/applications/utilities/mesh/conversion/ansysToFoam/ansysToFoam.L
+++ b/applications/utilities/mesh/conversion/ansysToFoam/ansysToFoam.L
@@ -77,11 +77,11 @@ label currentTypei = -1;
 // Dummy yywrap to keep yylex happy at compile time.
 // It is called by yylex but is not used as the mechanism to change file.
 // See <<EOF>>
-// #if YY_FLEX_SUBMINOR_VERSION < 34
-// extern "C" int yywrap()
-// #else
+#if YY_FLEX_MINOR_VERSION < 6 && YY_FLEX_SUBMINOR_VERSION < 34
+extern "C" int yywrap()
+#else
 int yyFlexLexer::yywrap()
-// #endif
+#endif
 {
     return 1;
 }
diff --git a/applications/utilities/mesh/conversion/fluent3DMeshToElmer/fluent3DMeshToElmer.L b/applications/utilities/mesh/conversion/fluent3DMeshToElmer/fluent3DMeshToElmer.L
index 153b917bf..da5115660 100644
--- a/applications/utilities/mesh/conversion/fluent3DMeshToElmer/fluent3DMeshToElmer.L
+++ b/applications/utilities/mesh/conversion/fluent3DMeshToElmer/fluent3DMeshToElmer.L
@@ -125,11 +125,11 @@ void uniquify(word& name, HashSet<word>& patchNames)
 // Dummy yywrap to keep yylex happy at compile time.
 // It is called by yylex but is not used as the mechanism to change file.
 // See <<EOF>>
-// #if YY_FLEX_SUBMINOR_VERSION < 34
-// extern "C" int yywrap()
-// #else
+#if YY_FLEX_MINOR_VERSION < 6 && YY_FLEX_SUBMINOR_VERSION < 34
+extern "C" int yywrap()
+#else
 int yyFlexLexer::yywrap()
-// #endif
+#endif
 {
     return 1;
 }
diff --git a/applications/utilities/mesh/conversion/fluent3DMeshToFoam/fluent3DMeshToFoam.L b/applications/utilities/mesh/conversion/fluent3DMeshToFoam/fluent3DMeshToFoam.L
index 4a6eaad20..766b26dd7 100644
--- a/applications/utilities/mesh/conversion/fluent3DMeshToFoam/fluent3DMeshToFoam.L
+++ b/applications/utilities/mesh/conversion/fluent3DMeshToFoam/fluent3DMeshToFoam.L
@@ -124,7 +124,7 @@ void uniquify(word& name, HashSet<word>& patchNames)
 // Dummy yywrap to keep yylex happy at compile time.
 // It is called by yylex but is not used as the mechanism to change file.
 // See <<EOF>>
-#if YY_FLEX_SUBMINOR_VERSION < 34
+#if YY_FLEX_MINOR_VERSION < 6 && YY_FLEX_SUBMINOR_VERSION < 34
 extern "C" int yywrap()
 #else
 int yyFlexLexer::yywrap()
diff --git a/applications/utilities/mesh/conversion/fluentMeshToFoam/fluentMeshToFoam.L b/applications/utilities/mesh/conversion/fluentMeshToFoam/fluentMeshToFoam.L
index 30ed08386..934bdd18c 100644
--- a/applications/utilities/mesh/conversion/fluentMeshToFoam/fluentMeshToFoam.L
+++ b/applications/utilities/mesh/conversion/fluentMeshToFoam/fluentMeshToFoam.L
@@ -103,7 +103,7 @@ wordList patchNameIDs(maxZoneID);
 // Dummy yywrap to keep yylex happy at compile time.
 // It is called by yylex but is not used as the mechanism to change file.
 // See <<EOF>>
-#if YY_FLEX_SUBMINOR_VERSION < 34
+#if YY_FLEX_MINOR_VERSION < 6 && YY_FLEX_SUBMINOR_VERSION < 34
 extern "C" int yywrap()
 #else
 int yyFlexLexer::yywrap()
diff --git a/applications/utilities/mesh/conversion/gambitToFoam/gambitToFoam.L b/applications/utilities/mesh/conversion/gambitToFoam/gambitToFoam.L
index 513d21ec0..fcb70223d 100644
--- a/applications/utilities/mesh/conversion/gambitToFoam/gambitToFoam.L
+++ b/applications/utilities/mesh/conversion/gambitToFoam/gambitToFoam.L
@@ -81,11 +81,11 @@ label nValuesForPatchFaces = 0;
 // Dummy yywrap to keep yylex happy at compile time.
 // It is called by yylex but is not used as the mechanism to change file.
 // See <<EOF>>
-// #if YY_FLEX_SUBMINOR_VERSION < 34
-// extern "C" int yywrap()
-// #else
+#if YY_FLEX_MINOR_VERSION < 6 && YY_FLEX_SUBMINOR_VERSION < 34
+extern "C" int yywrap()
+#else
 int yyFlexLexer::yywrap()
-// #endif
+#endif
 {
     return 1;
 }
diff --git a/applications/utilities/preProcessing/fluentDataToFoam/fluentDataToFoam.L b/applications/utilities/preProcessing/fluentDataToFoam/fluentDataToFoam.L
index a0051bcdb..7b632eb56 100644
--- a/applications/utilities/preProcessing/fluentDataToFoam/fluentDataToFoam.L
+++ b/applications/utilities/preProcessing/fluentDataToFoam/fluentDataToFoam.L
@@ -77,7 +77,7 @@ SLPtrList<FieldField<Field, scalar> > zoneData;
 // Dummy yywrap to keep yylex happy at compile time.
 // It is called by yylex but is not used as the mechanism to change file.
 // See <<EOF>>
-#if YY_FLEX_SUBMINOR_VERSION < 34
+#if YY_FLEX_MINOR_VERSION < 6 && YY_FLEX_SUBMINOR_VERSION < 34
 extern "C" int yywrap()
 #else
 int yyFlexLexer::yywrap()
diff --git a/src/meshTools/triSurface/triSurface/interfaces/STL/readSTLASCII.L b/src/meshTools/triSurface/triSurface/interfaces/STL/readSTLASCII.L
index 0792dd56e..a63fc7c04 100644
--- a/src/meshTools/triSurface/triSurface/interfaces/STL/readSTLASCII.L
+++ b/src/meshTools/triSurface/triSurface/interfaces/STL/readSTLASCII.L
@@ -53,11 +53,11 @@ int yyFlexLexer::yylex()
 // It is called by yylex but is not used as the mechanism to change file.
 // See <<EOF>>
 //! @cond dummy
-// #if YY_FLEX_SUBMINOR_VERSION < 34
-// extern "C" int yywrap()
-// #else
+#if YY_FLEX_MINOR_VERSION < 6 && YY_FLEX_SUBMINOR_VERSION < 34
+extern "C" int yywrap()
+#else
 int yyFlexLexer::yywrap()
-// #endif
+#endif
 {
     return 1;
 }
diff --git a/src/surfMesh/surfaceFormats/stl/STLsurfaceFormatASCII.L b/src/surfMesh/surfaceFormats/stl/STLsurfaceFormatASCII.L
index ecb74e7c1..e392ef8f6 100644
--- a/src/surfMesh/surfaceFormats/stl/STLsurfaceFormatASCII.L
+++ b/src/surfMesh/surfaceFormats/stl/STLsurfaceFormatASCII.L
@@ -50,7 +50,7 @@ int yyFlexLexer::yylex()
 // It is called by yylex but is not used as the mechanism to change file.
 // See <<EOF>>
 //! @cond dummy
-#if YY_FLEX_SUBMINOR_VERSION < 34
+#if YY_FLEX_MINOR_VERSION < 6 && YY_FLEX_SUBMINOR_VERSION < 34
 extern "C" int yywrap()
 #else
 int yyFlexLexer::yywrap()
diff --git a/src/thermophysicalModels/reactionThermo/chemistryReaders/chemkinReader/chemkinLexer.L b/src/thermophysicalModels/reactionThermo/chemistryReaders/chemkinReader/chemkinLexer.L
index 466d8e017..23dfca728 100644
--- a/src/thermophysicalModels/reactionThermo/chemistryReaders/chemkinReader/chemkinLexer.L
+++ b/src/thermophysicalModels/reactionThermo/chemistryReaders/chemkinReader/chemkinLexer.L
@@ -54,7 +54,7 @@ int yyFlexLexer::yylex()
 // It is called by yylex but is not used as the mechanism to change file.
 // See <<EOF>>
 //! @cond dummy
-#if YY_FLEX_SUBMINOR_VERSION < 34
+#if YY_FLEX_MINOR_VERSION < 6 && YY_FLEX_SUBMINOR_VERSION < 34
 extern "C" int yywrap()
 #else
 int yyFlexLexer::yywrap()