To rename the shortcodes from versions older than 1.5 you can run this SQL statement:
Please backup your database before running this query and replace YOUR_WORDPRESS_DATABASE with your wordpress database name.
UPDATE `YOUR_WORDPRESS_DATABASE`.`wp_posts` SET post_content = REPLACE( REPLACE( REPLACE( REPLACE( REPLACE( REPLACE( REPLACE( REPLACE( REPLACE(post_content, 'td_ad_box', 'td_block_ad_box') , 'td_authors', 'td_block_authors') , 'td_homepage_full_1', 'td_block_homepage_full_1') , 'td_popular_categoriesc', 'td_block_popular_categories') , 'td_video_vimeo', 'td_block_video_vimeo') , 'td_video_youtube', 'td_block_video_youtube') , 'td_text_with_title', 'td_block_text_with_title') , 'td_slide', 'td_block_slide') , 'td_social_counter', 'td_block_social_counter') WHERE (post_type = 'page' or post_type = 'post');