Q: I am looking to purchase the Uppababy Vista 2015. I plan on using it for two children. I see an upper and lower adapter available - when would I need to use those? A: For any 2-child configurations, Upper Adapter & Lower Adapter is required. The Rumbleseat includes the rumbleseat adapter. In the UPPER SEAT position, two adapters are needed with other brand infant seats: Upper Adapter + Brand Infant Car Seat Adapter. In the LOWER SEAT position, two adapters are needed with Chicco Infant Seat: Lower Adapter + Chicco Infant Car Seat Adapter. Use the handy chart below to find out what accessories are necessary for you to build the perfect Vista that will work for your family. And of course - if you have any questions - give us a call or post your questions below! Q: Can I use the 2015 Vista Rumbleseat with an older model Vista? No accessories designed for the seat or rumbleseat of the new 2015 Vista will fit onto any older model Vista. This includes car seat adapters as well.