There is no database change from 1.0 to 1.1. and ezcomments 1.1 will work on ezp4.2 with small problem like ezcomments 1.0 on ezp4.2 (see faq in http://projects.ez.no/ezcomments)
Documentation for fetching latest comment: http://ez.no/doc/extensions/ez_comments/setup_and_user_guide_1_1/template_fetch_functions/latest_comments_list