This plugin needs an update to work with php7. (and 8) @garethgillman has provided a fix. https://wordpress.org/support/topic/fix-for-php-7/ Once that's fixed it works really nice. Although it could also warn users that media files haven't been moved. Its not cool that @wordpressdotorg hasn't deployed that fix with an update to the plugin. Its almost like a core feature. For lots of people this is going to be one of their first experiences of Wordpress trying to migrate their old site. Sorry for whinging let me know how I can fix it myself if thats easier.

Why is this even being offered as a possibility when it has not been tested on newer versions of WP?

Update line 109 for fixed wrong import categories: Old code: //$categories[$cat_index] = $wpdb->escape( html_entity_decode( $category ) ); New code: $categories[$cat_index] = str_replace(array('<![CDATA[', ']]>'), '', $wpdb->escape( trim($category) ));

PHP Fatal error: Uncaught Error: Call to undefined function set_magic_quotes_runtime() in /var/www/wordpress/wp-content/plugins/rss-importer/rss-importer.php:72\nStack trace:\n#0 /var/www/wordpress/wp-content/plugins/rss-importer/rss-importer.php(178): RSS_Import->get_posts()\n#1 /var/www/wordpress/wp-content/plugins/rss-importer/rss-importer.php(204): RSS_Import->import()\n#2 /var/www/wordpress/wp-admin/admin.php(308): RSS_Import->dispatch()\n#3 {main}\n thrown in /var/www/wordpress/wp-content/plugins/rss-importer/rss-importer.php on line 72, referer: https://marvin.fablab.fau.de/wp-admin/admin.php?import=rss

Causes errors with current versions of both PHP and WordPress