Hello, I've updated my evolution packages on Fedora 28 from evolution-ews-3.28.1-1.fc28.x86_64 to evolution-ews-3.28.3-1.fc28.x86_64 and since then updating participants (adding/removing) on a meeting is not possible anymore. When I downgraded back to 3.28.1 it started to work again. There is something wrong with an XML being sent to MS Exchage, XSD validation fails with: "Cannot modify calendar object: The request failed schema validation: The element 'Updates' in namespace 'http://schemas.microsoft.com/exchange/services/2006/types' has invalid child element 'IsResponseRequested' in namespace 'http://schemas.microsoft.com/exchange/services/2006/types'. List of possible elements expected: 'AppendToItemField, SetItemField, DeleteItemField' in namespace 'http://schemas.microsoft.com/exchange/services/2006/types'." I can provide WSDL/XSDs from the server if required (previous mailing list post with these attached was rejected by an admin as too big). Best regards, Jiri -- Ing. Jiří Hofman Konzultant | +420 775 146 367 | jiri hofman email cz | LinkedIn IČ 01636537 | Fyzická osoba zapsaná v živnostenském rejstříku |