Add Last Modified Date to Post Byline
Paste function into your child theme's functions.php
file
<?php
function md_child_theme_byline_date() { ?>
<span class="byline-date-modified byline-item">
<i class="byline-item-icon md-icon-clock"></i> <?php _e( 'Last updated:', 'md' ); ?> <?php the_modified_date(); ?>
</span>
<?php }
add_action( 'md_hook_byline_bottom', 'md_child_theme_byline_date' );

Use this code snippet to add the last modified date to the post byline. This is useful to show on older articles as it reassures the content in the article is updated.