Apple have release a supplemental update to 10.13. via the App Store update process.
Mainly security fixes, especially with the new APFS. https://www.macrumors.com/2017/10/05/apple-releases-macos-high-sierra-10-13-supplemental-update/
Also available as a direct download for updating multiple Macs, see: http://support.apple.com/downloads/DL1937/en_US/macOSUpd10.13Supplemental.dmg
Both my APFS (SSD) MacBook Air & the HFS+ (Fusion drive) iMac show the update in the MAS, so I'm doing the direct download.