I asked my product specialist about upgrading to a bigger battery capacity in the future (i.e. 8 years) and got this response:
"Batteries will not be upgradable in the future.* As technology improves, their range may increase, but it will still be the same size battery pack.* You will be required to replace battery packs like for like."
I am shocked by this, as I don't see any technical or logical reason for this limitation. I am also confused how the same capacity batteries could provide increased range.