WP 4.0 got pushed back to next week. The tentative release date was Aug. 27. We also pushed BPS Pro 9.3 back a bit to take care of a couple of other things. BPS Pro 9.3 will be released between Sept. 1-3.
As it turns out Maintenance Mode does partially work on a Network/Multisite Subdomain site. The Primary site can be successfully put into MMode, but there are some undesirable issues/problems with doing that – it does not work 100% as intended. ie the entire site is put into MMode – all sites instead of individual sites. MMode on Subsites does not work at all due to using the path object value: $current_blog->path; for creating the template file name for Subdomain subsites instead of the domain object value: $current_blog->domain;. What we are going to do is in BPS Pro 9.3 we are going to hide the MMode menus for subsites and then in BPS Pro 9.4 we will have all the code completed and working for all Subdomain Primary and Subsite sites.