Sorry dor the late reply... but with the Christmas season...
In order to check the firmware version you have two choices:
1) Through the Zolo Audio app. You select the gear on the speaker you want to check on, and then you click on Information, and almost at the end of the list you will have the firmware version.
2) Through the Alexa App on your phone. You select the device you want to check on, and then on "About", there you can check the firmware version (date) and serial number. Latest firmware's date is 20181127 (27 of November of 2018), only the two latest firmwares show information there through the Alexa App, in prior versions this item was left blank.
In order to update the firmware, through the Zolo Audio app, selecting the gear on the device you want to update, select Information and choose the hours where the device you want to check for updates (you get a list with several time slots of three hours if I remember well). Once you have selected the time slot, mute your device, it's just a matter of time that it gets the update from the servers. You will notice that the device is getting the update once the light turn orange. One it is updated you can unmute it.
Hope this helps!