Use Middle Firmware for Indirect Upgrades

Sometimes you may need to upgrade devices by several versions, where a direct upgrade from current to desired version is not possible.
Using middle firmware means applying one or more firmware versions between the current version and the desired version during an upgrade sequence.

Add multiple policies using middle firmware

If you cannot go from firmware A to C without first installing B, then B is the middle firmware, and you must add two policies:

• One to upgrade from firmware A to B.
• A second policy to upgrade from firmware B to C.

For instructions on setting up policies, see Apply a New Firmware Version to Multiple Devices.

Inform users ahead of time

Note that the device will usually reboot after the new firmware is received. Depending on the event triggers you specify in your policy, this upgrade sequence will therefore cause a minimum of two reboots.
We strongly recommend informing users if you have to apply a middle-firmware policy. This is because:

• The user may see the downtime caused by this as considerable
• Users must avoid rebooting the device themselves during the upgrade sequence as this may harm the operation as well as the device.