If you are using HiveManager (rather than HiveManager Classic) you would want to go to Monitor> Check the box next to the AP> Update Devices> Check the box next to Upgrade HiveOS and Aerohive Switch Images> Choose the Upgrade to the specific version> Click Add/Remove.
In the new window, click on the plus icon in the top left corner> Choose. Select the file from your computer and add it to the HiveManager.
