diff --git a/doc/manual/installation.xml b/doc/manual/installation.xml
index b9358efd1d..2642bca1d7 100644
--- a/doc/manual/installation.xml
+++ b/doc/manual/installation.xml
@@ -57,14 +57,15 @@ repository.
To build the parser, very recent versions
of Bison and Flex are required. (This is because Nix needs GLR
support in Bison and reentrancy support in Flex.) For Bison, you need
-version 1.875c or higher (1.875 does not work),
-which can be obtained from the GNU FTP server.
-For Flex, you need version 2.5.31, which is available on SourceForge. Slightly
-older versions may also work, but ancient versions like the ubiquitous
-2.5.4a won't. Note that these are only required if you modify the
-parser or when you are building from the Subversion repository.
+version 2.3 or higher (1.875 does not work),
+which can be obtained from
+the GNU FTP
+server. For Flex, you need version 2.5.33, which is available
+on SourceForge.
+Slightly older versions may also work, but ancient versions like the
+ubiquitous 2.5.4a won't. Note that these are only required if you
+modify the parser or when you are building from the Subversion
+repository.
Nix uses Sleepycat's Berkeley DB and CWI's ATerm library. These
are included in the Nix source distribution. If you build from the
@@ -75,7 +76,7 @@ these packages. Alternatively, if you already have them installed,
you can use configure's
and options to point to their respective
locations. Note that Berkeley DB must be version
-4.4; other versions may not have compatible database formats.
+4.5; other versions may not have compatible database formats.