diff --git a/documentation/Doxyfile.in b/documentation/Doxyfile.in
index 80c9dafaa..669795747 100644
--- a/documentation/Doxyfile.in
+++ b/documentation/Doxyfile.in
@@ -1007,7 +1007,7 @@ COMPACT_LATEX          = NO
 # by the printer. Possible values are: a4, a4wide, letter, legal and
 # executive. If left blank a4wide will be used.
 
-PAPER_TYPE             = a4wide
+PAPER_TYPE             = a4
 
 # The EXTRA_PACKAGES tag can be to specify one or more names of LaTeX
 # packages that should be included in the LaTeX output.
@@ -1312,7 +1312,8 @@ EXTERNAL_GROUPS        = YES
 # The PERL_PATH should be the absolute path and name of the perl script
 # interpreter (i.e. the result of `which perl').
 
-PERL_PATH              = /usr/bin/perl
+#** obsolete as of Doxygen 1.8.16 (use default for older versions)
+#** PERL_PATH              = /usr/bin/perl
 
 #---------------------------------------------------------------------------
 # Configuration options related to the dot tool
@@ -1334,7 +1335,8 @@ CLASS_DIAGRAMS         = YES
 # the mscgen tool resides. If left empty the tool is assumed to be found in the
 # default search path.
 
-MSCGEN_PATH            =
+#** obsolete as of Doxygen 1.8.16, not used by FLTK anyway
+#** MSCGEN_PATH            =
 
 # If set to YES, the inheritance and collaboration graphs will hide
 # inheritance and usage relations if the target is undocumented