When the device says its 'up-to-date' but there is an upgrade available you can apply it as below...
Organization>Firmware Upgrades
Click the 'All networks' tab at the top
Tick the line corresponding to what you wish to update
Click 'Schedule upgrades'
In the 'Target firmware version' column, use the drop down to select the version you wish to upgrade to
Click Next
Now you can schedule the date/time when you wish the firmware to be updated