How to upgrade a Pure Moment Charge.

You need a usb-c cable, connected to a computer or phone that can see usb drives.

Down load the firmware from the Pure site: https://support.pure-audio.com/b/pure-support/en-US/kb/articles/how-to-perform-an-update-on-your-pure-moment

Connect the usb-c to your computer/device
Unplug and replug the Pure moment  from the mains, the device is in standby at this point. Press and hold the dial until the display reads USB FLASH. 

The Pure Moment will appear on your computer/device as a usb drive, this is incidentally how you can add your own "ambient sounds" to the device (or rob them off the device).

drop the .ufw file into the the root of this drive. Safely eject then unplug the cable, the display on the Pure Moment will change. Go to settings (home button, scroll to settings, press the dial) the first option should now be "update fw" click on that and the sub menu to start the update. DON'T REMOVE THE POWER!

 When it's finished you should be updated. I'd say going from v17 to v37 is a critical update, if I'd not been able to do the update I'd have sent the device back, the sound was way too much bass and not being able to adjust the light timer would have also been a reason to return ...