diff --git a/libstdc++-v3/doc/html/manual/debug.html b/libstdc++-v3/doc/html/manual/debug.html
index a5f51569e00..1623cd30486 100644
--- a/libstdc++-v3/doc/html/manual/debug.html
+++ b/libstdc++-v3/doc/html/manual/debug.html
@@ -250,4 +250,4 @@
   with C++11 and later standards. They might be removed at a future date.
   </p></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="using_exceptions.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="using.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="std_contents.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Exceptions </td><td width="20%" align="center"><a accesskey="h" href="../index.html">Home</a></td><td width="40%" align="right" valign="top"> Part II. 
     Standard Contents
-  </td></tr></table></div></body></html>
+  </td></tr></table></div></body></html>
\ No newline at end of file
diff --git a/libstdc++-v3/doc/html/manual/documentation_hacking.html b/libstdc++-v3/doc/html/manual/documentation_hacking.html
index 047a62e0831..6b462b44acf 100644
--- a/libstdc++-v3/doc/html/manual/documentation_hacking.html
+++ b/libstdc++-v3/doc/html/manual/documentation_hacking.html
@@ -112,9 +112,10 @@
       supported, and are always aliased to dummy rules. These
       unsupported formats are: <span class="emphasis"><em>info</em></span>,
       <span class="emphasis"><em>ps</em></span>, and <span class="emphasis"><em>dvi</em></span>.
-    </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="doc.doxygen"></a>Doxygen</h3></div></div></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="doxygen.prereq"></a>Prerequisites</h4></div></div></div><div class="table"><a id="table.doxygen_prereq"></a><p class="title"><strong>Table B.1. Doxygen Prerequisites</strong></p><div class="table-contents"><table class="table" summary="Doxygen Prerequisites" border="1"><colgroup><col align="center" class="c1" /><col align="center" class="c2" /><col align="center" class="c3" /></colgroup><thead><tr><th align="center">Tool</th><th align="center">Version</th><th align="center">Required By</th></tr></thead><tbody><tr><td align="center">coreutils</td><td align="center">8.5</td><td align="center">all</td></tr><tr><td align="center">bash</td><td align="center">4.1</td><td align="center">all</td></tr><tr><td align="center">doxygen</td><td align="center">1.7.6.1</td><td align="center">all</td></tr><tr><td align="center">graphviz</td><td align="center">2.26</td><td align="center">graphical hierarchies</td></tr><tr><td align="center">pdflatex</td><td align="center">2007-59</td><td align="center">pdf output</td></tr></tbody></table></div></div><br class="table-break" /><p>
+    </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="doc.doxygen"></a>Doxygen</h3></div></div></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="doxygen.prereq"></a>Prerequisites</h4></div></div></div><div class="table"><a id="table.doxygen_prereq"></a><p class="title"><strong>Table B.1. Doxygen Prerequisites</strong></p><div class="table-contents"><table class="table" summary="Doxygen Prerequisites" border="1"><colgroup><col align="center" class="c1" /><col align="center" class="c2" /><col align="center" class="c3" /></colgroup><thead><tr><th align="center">Tool</th><th align="center">Version</th><th align="center">Required By</th></tr></thead><tbody><tr><td align="center">coreutils</td><td align="center">8.5</td><td align="center">all</td></tr><tr><td align="center">bash</td><td align="center">4.1</td><td align="center">all</td></tr><tr><td align="center">doxygen</td><td align="center">1.9.1</td><td align="center">all</td></tr><tr><td align="center">graphviz</td><td align="center">2.26</td><td align="center">graphical hierarchies</td></tr><tr><td align="center">pdflatex</td><td align="center">2007-59</td><td align="center">pdf output</td></tr></tbody></table></div></div><br class="table-break" /><p>
 	Prerequisite tools are Bash 2.0 or later,
-	<a class="link" href="https://www.doxygen.nl" target="_top">Doxygen</a>, and
+	<a class="link" href="https://www.doxygen.nl" target="_top">Doxygen</a>
+	1.9.1 or later (for best results use at least 1.9.6), and
 	the <a class="link" href="http://www.gnu.org/software/coreutils/" target="_top">GNU
 	coreutils</a>. (GNU versions of find, xargs, and possibly
 	sed and grep are used, just because the GNU versions make
diff --git a/libstdc++-v3/doc/html/manual/setup.html b/libstdc++-v3/doc/html/manual/setup.html
index d8c5ff65cff..67bb6c108a1 100644
--- a/libstdc++-v3/doc/html/manual/setup.html
+++ b/libstdc++-v3/doc/html/manual/setup.html
@@ -22,8 +22,7 @@
   Because libstdc++ is part of GCC, the primary source for
    installation instructions is
    <a class="link" href="https://gcc.gnu.org/install/" target="_top">the GCC install page</a>.
-   In particular, the list of prerequisite software needed to build
-   the library
+   In particular, list of prerequisite software needed to build the library
    <a class="link" href="https://gcc.gnu.org/install/prerequisites.html" target="_top">
    starts with those requirements.</a> The same pages also list
    the tools you will need if you wish to modify the source.
diff --git a/libstdc++-v3/doc/html/manual/using_exceptions.html b/libstdc++-v3/doc/html/manual/using_exceptions.html
index f3556ef9d75..706b27e1479 100644
--- a/libstdc++-v3/doc/html/manual/using_exceptions.html
+++ b/libstdc++-v3/doc/html/manual/using_exceptions.html
@@ -166,8 +166,8 @@ exception neutrality and exception safety.
     implicitly generated magic necessary to
     support <code class="literal">try</code> and <code class="literal">catch</code> blocks
     and thrown objects. (Language support
-    for <code class="literal">-fno-exceptions</code> is documented in the GNU
-    GCC <a class="link" href="https://gcc.gnu.org/onlinedocs/gcc/Code-Gen-Options.html#Code-Gen-Options" target="_top">manual</a>.)
+    for <code class="literal">-fno-exceptions</code> is documented in the GCC 
+    <a class="link" href="https://gcc.gnu.org/onlinedocs/gcc/Code-Gen-Options.html#Code-Gen-Options" target="_top">manual</a>.)
   </p><p>Before detailing the library support
     for <code class="literal">-fno-exceptions</code>, first a passing note on
     the things lost when this flag is used: it will break exceptions
diff --git a/libstdc++-v3/doc/html/manual/using_headers.html b/libstdc++-v3/doc/html/manual/using_headers.html
index 5f669862654..49a82614344 100644
--- a/libstdc++-v3/doc/html/manual/using_headers.html
+++ b/libstdc++-v3/doc/html/manual/using_headers.html
@@ -186,5 +186,5 @@ g++ -Winvalid-pch -I. -include stdc++.h -H -g -O2 hello.cc -o test.exe
 ! ./stdc++.h.gch
 . /mnt/share/bld/H-x86-gcc.20071201/include/c++/4.3.0/iostream
 . /mnt/share/bld/H-x86-gcc.20071201include/c++/4.3.0/string
-</pre><p>The exclamation point to the left of the <code class="code">stdc++.h.gch</code> listing means that the generated PCH file was used.</p><p></p><p> Detailed information about creating precompiled header files can be found in the GCC <a class="link" href="https://gcc.gnu.org/onlinedocs/gcc/Precompiled-Headers.html" target="_top">documentation</a>.
+</pre><p>The exclamation point to the left of the <code class="code">stdc++.h.gch</code> listing means that the generated PCH file was used.</p><p></p><p>Detailed information about creating precompiled header files can be found in the GCC <a class="link" href="https://gcc.gnu.org/onlinedocs/gcc/Precompiled-Headers.html" target="_top">documentation</a>.
 </p></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="using.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="using.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="using_macros.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Chapter 3. Using </td><td width="20%" align="center"><a accesskey="h" href="../index.html">Home</a></td><td width="40%" align="right" valign="top"> Macros</td></tr></table></div></body></html>
\ No newline at end of file
diff --git a/libstdc++-v3/doc/xml/manual/documentation_hacking.xml b/libstdc++-v3/doc/xml/manual/documentation_hacking.xml
index 692b724ca11..ffd0fc7f568 100644
--- a/libstdc++-v3/doc/xml/manual/documentation_hacking.xml
+++ b/libstdc++-v3/doc/xml/manual/documentation_hacking.xml
@@ -238,7 +238,7 @@
 
     <row>
       <entry>doxygen</entry>
-      <entry>1.7.6.1</entry>
+      <entry>1.9.1</entry>
       <entry>all</entry>
     </row>
 
@@ -261,7 +261,8 @@
 
       <para>
 	Prerequisite tools are Bash 2.0 or later,
-	<link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="https://www.doxygen.nl">Doxygen</link>, and
+	<link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="https://www.doxygen.nl">Doxygen</link>
+	1.9.1 or later (for best results use at least 1.9.6), and
 	the <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.gnu.org/software/coreutils/">GNU
 	coreutils</link>. (GNU versions of find, xargs, and possibly
 	sed and grep are used, just because the GNU versions make
