Hi Scott,
Are you sure the MLA requires such an older version of BuddyPress? BP 4.2 was released in December 2018.
If that is the case, CBOX 1.1.1 is the release where we bumped compatibility to BuddyPress 4.2. The plugin versions for CBOX 1.1.1 can be found in the plugin manifest here:
https://github.com/cuny-academic-commons/commons-in-a-box/blob/1.1.1/includes/classic/plugins.php#L76
It would be wise for the MLA to upgrade to the latest version though. If certain custom plugin functionality for the MLA is breaking in the latest BuddyPress release, it would be great to find what the cause is.