Hitachi AllPlay Adaptor User Manual page 16

2， After you select your speaker, continue to "Settings" and then
press the " " button.
3， Scroll down to the "Firmware" section and select "Check for
updates now". The app will then check for updates and if there is
an update available for your speaker, follow the instructions
provided by the app to update.
HITACHI Allplay Adaptor User`s Guide
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