Update instructions for updating Header Tags SEO version 3.1.6 to
Header Tags SEO V 3.1.7 by Jack_mcs

1) Run the following mysql statement:

ALTER TABLE `headertags_default` ADD `meta_canonical` TINYINT( 1 ) NOT NULL DEFAULT '1' AFTER `meta_unspam` ;

2) Replace the following files (or just upload all of the files in catalog/admin/):

admin/header_tags_fill_tags.php
admin/includes/languages/english/header_tags_seo.php
admin/header_tags_seo.php
admin/includes/functions/header_tags.php
includes/functions/header_tags.php

3) Replace the includes/header_tags.php file or make the following edits to it. In most
cases, you can just replace it and run Add Missing Pages from page Control. But if you
have pseudo pages added, replacing this file will cause those to be lost and you would have
to re-enter them.

FIND (around line 17):

$header_tags_array = array();

ADD ABOVE IT:

$canonical_url = '';

FINE (near end of file):

if (tep_not_null($canonical_url))  echo ' <link rel="canonical" href="'.$canonical_url.'" >'. "\n";

ADD AFTER:

else if ($defaultTags['meta_canonical'])  echo ' <link rel="canonical" href="'.GetCanonicalURL().'" >'. "\n";
