I appear to have the same issue… were you able to solve?
By the way, I am working on a site that over the years tried many shortcode plugins. Yours is the best. Thank you for it.
Following upgrade to WordPress 5.21, plugin throws error:
Uncaught Error: Class 'Shortcoder_Metadata' not found in /wp-content/plugins/shortcoder/shortcoder.php:165 Stack trace: #0 /wp-content/plugins/shortcoder/shortcoder.php(113): Shortcoder::replace_wp_params('<code>\r\n<script...', '') #1 /wp-includes/shortcodes.php(325): Shortcoder::execute_shortcode(Array, '', 'sc') #2 [internal function]: do_shortcode_tag(Array) #3 /wp-includes/shortcodes.php(199): preg_replace_callback('/\\[(\\[?)(sc)(?!...', 'do_shortcode_ta...', '<p><img /><img />apply_filters('<p><img class="...', Array) #6 /wp-includes/post-template.php(247): apply_filters('the_content', '<img class="ali...') #7 /wp-content/themes/frontier/loop-single.php(77): the_content() in /wp-content/plugins/shortcoder/shortcoder.php on line 165
