Apple released iOS version 12.0.1 on October 8th 2018 to fix some recent issues on iPhones and iPads, which includes iPhone X battery charging problems, as well as security updates.
A full list of Apple device security updates is available at support.apple.com/en-us/HT201222. Instructions on how to install updates on Apple iOS devices are available at support.apple.com/en-us/HT204204.