Changes to Models S and X allow them to travel longer without larger batteries
This "continuous deployment" for cars must be a logistical nightmare.  To do repairs for a given vehicle, keeping track of what parts are backward compatible would be challenging.  What if it's a compatibility breaking change?  Then keeping inventory for older cars would become problematic.Unless they do design with maximum compatibility.  Then it gets interesting as upgrades are possible.While B.EV cars maintenance is low, my car 7 months into ownership revealed bad battery cells that needed replacing.  If the car was say five years old, would this replacement have been possible?