Download the latest release from Mitel Online, put the unzipped folder in a USB flash drive, insert flash drive in the front USB port, go through LCD navigation to System > Upgrade. Or, you'll have to set up a TFTP server, put unzipped folder in the TFTP folder, log in to the web portal of the 5000, go to Upgrade and Uploads, enter TFTP server IP address and play with the syntax of the path until it actually works. USB method is the easiest way.