I’ve been working hard on a new WordPress theme, but I needed the theme to be compatible with both WordPress 2.6 and 2.7.

If you’re a theme developer, you already know how hard it’s going to be to make your 2.7 theme backward compatible because of all the new features being added.

I won’t go into the details of how to put together a comments.php file here. There are plenty of tutorials and themes to look at for that.

Check out Otto’s WordPress 2.7 comments enhancements tutorial to add all the extra features to your theme’s comments file.

Setting up the comment files

Let’s assume you start with a WordPress 2.6-ready comments file. What you need to do is save that file as legacy.comments.php in your theme directory.

Next, you need to create your WordPress 2.7-only comments file and save it as comments.php.

What we’ll be doing is checking the version of WordPress the theme user has installed. If they’re using 2.7, we’ll call comments.php. If they’re using 2.6 or below, we’ll use legacy.comments.php.

In your theme’s functions.php file, add this code:

<?php

add_filter('comments_template', 'legacy_comments');

function legacy_comments($file) {

	if(!function_exists('wp_list_comments')) : // WP 2.7-only check
		$file = TEMPLATEPATH . '/legacy.comments.php';
	endif;

	return $file;
}

?>

That’s it. All we did was filter the comments_template.

So, if you’re looking to add a little backward compatibility to your WordPress theme, this should help a bit.

Other resources

• comments_template filter