The Stokke® Crusi™ chassis is compatible with all Stokke® Xplory® and Crusi™ seats, even those of earlier Stokke® Xplory® models. However, when using seats of earlier Stokke® Xplory® models in combination with the Stokke® Crusi™ Sibling Seat, only seats with serial numbers 280000 or higher have been adapted and can be used in the sibling solution.