Is it possible to make a subsite a different version of Wordpress than the multisite? There is a plugin I would like to use that is only compatible up to WP version 3.9.2. Can that particular subsite I would like to use it on run only the WP 3.9.2 rather than what the multisite is (which is now WP 4.1)? If so, how and how can I lock it for that subsite to be sure it is not upgraded until needed (i.e. after that plugin is tested and compatible with newer versions)?