With the change of To prepare ADvendio to become Lightning Ready we included a lot of new custom tabs for our many objects and pages (to this will help support the navigation in Lightning Experience in a better way). This These tabs however could might lead to problems with the update of an old while updating to ADvendio version to 2.82 . If you in the case that you have had build your own custom tabs. You might receive an error message that some about existing custom tabs already exist, please delete them and repeat the installation. Afterwards the tabs will be back again reappear as part of the ADvendio Package, so that your users can access them.