We are excited to announce that we have launched our new Hive Community! HiveNation will remain as an archive, but all new posts, discussions, and articles will be created on Hive Community. You can visit our new community at thehivecommunity.aerohive.com
This is an old post but thought I might answer anyway. There are multiple ways to access the update option but I like to do it via the Configuration Tab under Devices. Select the devices and choose the Update button then Advanced Upload and Activate HiveOS Firmware.