Using IC2 can allow a user to upgrade only one device, a set of devices, or all devices firmware at one time. I will be covering how it can be done from just the Device Level here, but the same steps can be applied at the Group Level and at the Organization Level.
Navigate to the device that you wish to upgrade in IC2. Hover over Settings and click on Firmware Management.
Select the firmware version that the unit will be upgraded to. If a special version of firmware has been provided select Custom. The provided Firmware URL can be added and verified here. The steps will be the same after loading the custom firmware version. If the firmware should be pushed out right now select Immediately. If the firmware should be pushed out at a later time select Scheduled and enter the date and time. After the appropriate schedule has been set click Save Changes
IC2 will let the unit know that a firmware upgrade is pending and will push the firmware down at the appropriate time.