diff --git a/doc/manual/installation.xml b/doc/manual/installation.xml
index fdab71fc0f..e67704fba2 100644
--- a/doc/manual/installation.xml
+++ b/doc/manual/installation.xml
@@ -166,11 +166,10 @@ a source distribution.</para>
 
   <listitem><para>Recent versions of Bison and Flex to build the
   parser.  (This is because Nix needs GLR support in Bison and
-  reentrancy support in Flex.)  For Bison, you need version 2.3 or
-  higher (1.875 does <emphasis>not</emphasis> work), which can be
-  obtained from the <link
+  reentrancy support in Flex.)  For Bison, you need version 2.6, which
+  can be obtained from the <link
   xlink:href="ftp://alpha.gnu.org/pub/gnu/bison">GNU FTP
-  server</link>.  For Flex, you need version 2.5.33, which is
+  server</link>.  For Flex, you need version 2.5.35, which is
   available on <link
   xlink:href="http://lex.sourceforge.net/">SourceForge</link>.
   Slightly older versions may also work, but ancient versions like the
diff --git a/release.nix b/release.nix
index 673d7f9d19..5b38fc1c60 100644
--- a/release.nix
+++ b/release.nix
@@ -19,7 +19,7 @@ let
         inherit officialRelease;
 
         buildInputs =
-          [ curl bison25 flex2535 perl libxml2 libxslt w3m bzip2
+          [ curl bison flex2535 perl libxml2 libxslt w3m bzip2
             tetex dblatex nukeReferences pkgconfig sqlite git
           ];