Attention: With the change of ADvendio to become Lightning Ready we included a lot of custom tabs for our objects and pages (to support the navigation in Lightning Experience in a better way). This however could lead to problems with the update of an old ADvendio version to 2.82. If you receive an error message that some custom tabs already exist, please delete them and repeat the installation. Afterwards the tabs will be back again as part of the ADvendio Package, so your users can access them.