This system was released in 2016, so the very last support for it would have been in 2021 -- all OEMs EOL (end of life) models at this point. That said, OEM batteries are still available: [URL]  
A bit of a quandary here. My 2017 out of warranty XPS 13 9360 battery will no longer hold a charge, not even enough to turn on the PC now. It appears that there is not an original Dell replacement available but the advice is not to purchase off the internet. This effectively now renders my laptop unusable other than plugged in to the mains. Very disappointed that a company of Dell's stature no longer support this given the number of units that must be in circulation.
XPS 13 9360, battery replacement