Along with iOS 13.5, iPadOS 13.5 and tvOS 13.4.5, Apple has also released a new software version – 13.4.5 for the HomePod. The version numbers are different from iOS because during the beta cycle of iOS 13.4.5, Apple switched to iOS 13.5 to include the new COVID-19 Exposure API. Read more about the features and changes on iOS 13.5 here.
According to Apple, “HomePod software version 13.4.5 includes general improvements for stability and quality” This update has improvements and stability for the Quality of the HomePod.
Your HomePod should update automatically, however, if you want to update it manually, you can Go to the Home App on your iPhone or iPad, tap on the home icon of the top left-hand side of your iPhone display, if you have multiple homes set up then select a home, scroll down until you find the “SPEAKER & TVS” Section and tap on Software update. If the update does not show up already swipe down to refresh for the update. Once you tap on update, all your HomePods will be updated at the same time.