| UpdateItems(IEnumerable<Item>, FolderId, ConflictResolutionMode, Nullable<MessageDisposition>, Nullable<SendInvitationsOrCancellationsMode>) | Updates multiple items in a single EWS call. UpdateItems does not support items that have unsaved attachments. |
| UpdateItems(IEnumerable<Item>, FolderId, ConflictResolutionMode, Nullable<MessageDisposition>, Nullable<SendInvitationsOrCancellationsMode>, Boolean, CancellationToken) | Updates multiple items in a single EWS call. UpdateItems does not support items that have unsaved attachments. |