"To upgrade the cabin" means to improve or enhance the interior of a vehicle, usually referring to adding more luxurious or advanced features to make it more comfortable and appealing. Full definition
For premium driving comfort, feel free to upgrade your cabin with available leather - upholstered, heated seats and a heated steering wheel. (tempechryslerjeepdodge.net)
Here's where I'm going with this: I'd take flying in upgraded cabins over hotel perks any day. (pointsmilesandmore.com)
Since we've been planning for it for several years in our financial plan, I have no hesitation in relaxing and «enjoying the process» of upgrading our cabin. (theretirementmanifesto.com)