Compatibility classes in vaadin 8

how we can do downward compatibility for Item,AbstractSelect
Field
InvalidValueException
OptionGroup
Property
DefaultFieldFactory
QueryDelegate
OrderBy
FreeformStatementDelegate
classes in vaadin8

Hi,

you need to include the Compatibility packages. See https://vaadin.com/docs/v8/framework/migration/migrating-to-vaadin8.html for more information.

-Olli