Hi , after upgrading kentico 8.2 to 9 , the class 'CMSAbstractLanguageWebPart' doesn't exist anymore : The type or namespace name 'CMSAbstractLanguageWebPart' could not be found (are you missing a using directive or an assembly reference?) ,someone can help ?
Did you read the upgrade instructions? There is a list of abandoned webparts and webparts inheriting this class are on this list.
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