diff --git a/install/ini.xml b/install/ini.xml
index 5851ba31ac..41d4bc47f0 100644
--- a/install/ini.xml
+++ b/install/ini.xml
@@ -33,12 +33,20 @@
     <listitem>
      <simpara>
       As of PHP 5.2.0, the location of the <literal>php.ini</literal> file
-      can be set for different versions of PHP. The following registry keys
+      can be set for different versions of PHP. The root of the registry keys depends on 32- or 64-bitness of the installed OS and PHP.
+      For 32-bit PHP on a 32-bit OS or a 64-bit PHP on a 64-bit OS use <literal>[(HKEY_LOCAL_MACHINE\SOFTWARE\PHP]</literal> for 32-bit version of PHP on a 64-bit OS use <literal>[HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\PHP]</literal>] instead.
+      For same bitness installation the following registry keys
       are examined in order:
       <literal>[HKEY_LOCAL_MACHINE\SOFTWARE\PHP\x.y.z]</literal>,
       <literal>[HKEY_LOCAL_MACHINE\SOFTWARE\PHP\x.y]</literal> and
       <literal>[HKEY_LOCAL_MACHINE\SOFTWARE\PHP\x]</literal>, where
-      x, y and z mean the PHP major, minor and release versions. If there is a
+      x, y and z mean the PHP major, minor and release versions.
+      For 32 bit versions of PHP on a 64 bit OS the following registry keys are examined in order:
+      <literal>[HKEY_LOCAL_MACHINE\SOFTWARE\WOW6421Node\PHP\x.y.z]</literal>,
+      <literal>[HKEY_LOCAL_MACHINE\SOFTWARE\WOW6421Node\PHP\x.y]</literal> and
+      <literal>[HKEY_LOCAL_MACHINE\SOFTWARE\WOW6421Node\PHP\x]</literal>, where
+      x, y and z mean the PHP major, minor and release versions.
+      If there is a
       value for <literal>IniFilePath</literal> in any of these keys, the first
       one found will be used as the location of the <literal>php.ini</literal>
       (Windows only).
@@ -46,7 +54,8 @@
     </listitem>
     <listitem>
      <simpara>
-      <literal>[HKEY_LOCAL_MACHINE\SOFTWARE\PHP]</literal>, value of
+      <literal>[HKEY_LOCAL_MACHINE\SOFTWARE\PHP]</literal> or
+      <literal>[HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\PHP]</literal>, value of
       <literal>IniFilePath</literal> (Windows only).
      </simpara>
     </listitem>