WordPress RSS feed template for my microcast

feed-microcast.php

<?php
/**
 * RSS2 Feed Template for displaying RSS2 Posts feed.
 * Modified for microcast 
 * Based on template found https://css-tricks.com/roll-simple-wordpress-podcast-plugin
 *
 */

$numposts = 50; // number of posts in feed
$posts = query_posts('showposts='.$numposts.'&cat=652');

header('Content-Type: ' . feed_content_type('rss2') . '; charset=' . get_option('blog_charset'), true);
$more = 1;

echo '<?xml version="1.0" encoding="'.get_option('blog_charset').'"?'.'>';

/**
 * Fires between the xml and rss tags in a feed.
 *
 * @since 4.0.0
 *
 * @param string $context Type of feed. Possible values include 'rss2', 'rss2-comments',
 *                        'rdf', 'atom', and 'atom-comments'.
 */
do_action( 'rss_tag_pre', 'rss2' );
?>
<rss version="2.0"
	xmlns:itunes="http://www.itunes.com/dtds/podcast-1.0.dtd"
	xmlns:content="http://purl.org/rss/1.0/modules/content/"
	xmlns:wfw="http://wellformedweb.org/CommentAPI/"
	xmlns:dc="http://purl.org/dc/elements/1.1/"
	xmlns:atom="http://www.w3.org/2005/Atom"
	xmlns:sy="http://purl.org/rss/1.0/modules/syndication/"
	xmlns:slash="http://purl.org/rss/1.0/modules/slash/"
	<?php
	/**
	 * Fires at the end of the RSS root to add namespaces.
	 *
	 * @since 2.0.0
	 */
	do_action( 'rss2_ns' );
	?>
>

<channel>
	<title>John's Microcast</title>
	<atom:link href="<?php self_link(); ?>" rel="self" type="application/rss+xml" />
	<link>http://johnjohnston.info/blog/category/microcast/</link>
	
    <language><?php echo get_bloginfo ( 'language' ); ?></language>
    <copyright><?php echo date('Y'); ?> <?php echo get_bloginfo('name'); ?></copyright>
    
    <itunes:author><?php echo get_bloginfo('name'); ?></itunes:author>
    <itunes:summary>A microcast by John Johnston</itunes:summary>
	
	<description>A microcast by John Johnston</description>
	
    <itunes:owner>
      <itunes:name><?php echo get_bloginfo('name'); ?></itunes:name>
      <itunes:email><?php echo get_bloginfo('admin_email'); ?></itunes:email>
    </itunes:owner>
	
    <itunes:image href="http://johnjohnston.info/blog/wp-content/uploads/2018/08/ravenlogo-1400.png" />
    
    <itunes:category text="Education">
    </itunes:category>
    <itunes:explicit>no</itunes:explicit>
	
	
	<lastBuildDate><?php
		$date = get_lastpostmodified( 'GMT' );
		echo $date ? mysql2date( 'r', $date, false ) : date( 'r' );
	?></lastBuildDate>
	<sy:updatePeriod><?php
		$duration = 'hourly';

		/**
		 * Filters how often to update the RSS feed.
		 *
		 * @since 2.1.0
		 *
		 * @param string $duration The update period. Accepts 'hourly', 'daily', 'weekly', 'monthly',
		 *                         'yearly'. Default 'hourly'.
		 */
		echo apply_filters( 'rss_update_period', $duration );
	?></sy:updatePeriod>
	<sy:updateFrequency><?php
		$frequency = '1';

		/**
		 * Filters the RSS update frequency.
		 *
		 * @since 2.1.0
		 *
		 * @param string $frequency An integer passed as a string representing the frequency
		 *                          of RSS updates within the update period. Default '1'.
		 */
		echo apply_filters( 'rss_update_frequency', $frequency );
	?></sy:updateFrequency>
	<?php
	/**
	 * Fires at the end of the RSS2 Feed Header.
	 *
	 * @since 2.0.0
	 */
	//do_action( 'rss2_head');

	while( have_posts()) : the_post();
	?>
    <item>
      <title><?php the_title_rss(); ?></title>
      <itunes:author><?php echo get_bloginfo('name'); ?></itunes:author>
      <itunes:summary><![CDATA[<?php echo $content; ?>]]></itunes:summary>
      <?php // Retrieve just the URL of the Featured Image: http://codex.wordpress.org/Function_Reference/wp_get_attachment_image_src
      if (has_post_thumbnail( $post->ID ) ): ?>
        <?php $image = wp_get_attachment_image_src( get_post_thumbnail_id( $post->ID ), 'full' ); ?>
        <itunes:image href="<?php echo $image[0]; ?>" />
      <?php endif; ?>
     
      <?php echo rss_enclosure()?>
      
      <guid><?php the_guid(); ?></guid>
		<pubDate><?php echo mysql2date('D, d M Y H:i:s +0000', get_post_time('Y-m-d H:i:s', true), false); ?></pubDate>
     </item>
	<?php endwhile; ?>
</channel>
</rss>