diff --git a/docs/doxygen-dev/Doxyfile b/docs/doxygen-dev/Doxyfile
index b8412f61ef..c3109400bf 100755
--- a/docs/doxygen-dev/Doxyfile
+++ b/docs/doxygen-dev/Doxyfile
@@ -2053,7 +2053,8 @@ EXTERNAL_PAGES         = NO
 # interpreter (i.e. the result of 'which perl').
 # The default file (with absolute path) is: /usr/bin/perl.
 
-PERL_PATH              = /usr/bin/perl
+# Obsolete tag
+# PERL_PATH              = /usr/bin/perl
 
 #---------------------------------------------------------------------------
 # Configuration options related to the dot tool
@@ -2075,7 +2076,8 @@ CLASS_DIAGRAMS         = NO
 # the mscgen tool resides. If left empty the tool is assumed to be found in the
 # default search path.
 
-MSCGEN_PATH            =
+# Obsolete tag
+#MSCGEN_PATH            =
 
 # You can include diagrams made with dia in doxygen documentation. Doxygen will
 # then run dia to produce the diagram and insert it in the documentation. The
diff --git a/docs/doxygen-user/Doxyfile b/docs/doxygen-user/Doxyfile
index 8295d9df5a..6eb71ae8f8 100644
--- a/docs/doxygen-user/Doxyfile
+++ b/docs/doxygen-user/Doxyfile
@@ -2053,7 +2053,8 @@ EXTERNAL_PAGES         = NO
 # interpreter (i.e. the result of 'which perl').
 # The default file (with absolute path) is: /usr/bin/perl.
 
-PERL_PATH              = /usr/bin/perl
+# Obsolete tag
+#PERL_PATH              = /usr/bin/perl
 
 #---------------------------------------------------------------------------
 # Configuration options related to the dot tool
@@ -2075,7 +2076,8 @@ CLASS_DIAGRAMS         = NO
 # the mscgen tool resides. If left empty the tool is assumed to be found in the
 # default search path.
 
-MSCGEN_PATH            =
+# Obsolete tag
+#MSCGEN_PATH            =
 
 # You can include diagrams made with dia in doxygen documentation. Doxygen will
 # then run dia to produce the diagram and insert it in the documentation. The
diff --git a/docs/doxygen/Doxyfile b/docs/doxygen/Doxyfile
index 649fa51fc0..6490edacd6 100644
--- a/docs/doxygen/Doxyfile
+++ b/docs/doxygen/Doxyfile
@@ -2094,7 +2094,8 @@ EXTERNAL_PAGES         = YES
 # interpreter (i.e. the result of 'which perl').
 # The default file (with absolute path) is: /usr/bin/perl.
 
-PERL_PATH              = /usr/bin/perl
+# Obsolete tag
+# PERL_PATH              = /usr/bin/perl
 
 #---------------------------------------------------------------------------
 # Configuration options related to the dot tool
@@ -2116,7 +2117,8 @@ CLASS_DIAGRAMS         = NO
 # the mscgen tool resides. If left empty the tool is assumed to be found in the
 # default search path.
 
-MSCGEN_PATH            =
+# Obsolete tag
+# MSCGEN_PATH            =
 
 # You can include diagrams made with dia in doxygen documentation. Doxygen will
 # then run dia to produce the diagram and insert it in the documentation. The