The Apple HomePod currently comes with software version 11.2.5 and is set to update automatically, however some may like to know if they are running the latest software especially if they have switched off the automatic update, checking if you are on the latest firmware is easy to do.
Open the Home app and tap
Scroll down to speakers and tap Software Update
This screen now shows you which firmware version you are on and if it is up to date.
Pif you would like to switch off Automatic updates you can simply toggle the tab above.