Added attributes into <html> of userguide for valid html.
diff --git a/user_guide/installation/upgrade_154.html b/user_guide/installation/upgrade_154.html
index 07dfa5d..6e8316c 100644
--- a/user_guide/installation/upgrade_154.html
+++ b/user_guide/installation/upgrade_154.html
@@ -1,5 +1,5 @@
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
-<html>
+<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<title>CodeIgniter User Guide : Upgrading from 1.5.3 to 1.5.4</title>