Mayo now has a default Main menu like Bartik to give a starter menu that's responsive on all devices. Changes were made to make it compatible with the Superfish module that many Mayo users have counted on in the past.
See Mayo theme - Moderately Critical - Cross Site Scripting (XSS) - SA-CONTRIB-2015-164
Removed admin settings for margins associated with logo, site name, and slogan to fix #2550593. Positioned with padding in styles.css
Issue #2509832 by Reg: Notice: Array to string conversion in mayo_get_plugins() (line 34 of .../mayo/inc/plugins.inc)
array_unique error corrected.
Improved styling for tabs.
Add feature to display breadcrumb Bartik style.