Important Notices for Upgrading FortiOS

Special builds

Every now and then a “Special Build” is created for some specific purpose and some companies will put these into production. These special builds are not part of the normal upgrade path QA process and therefore have a greater risk of variance from what is normally expected in an upgrade. The table of the upgrade path is based on the Release Notes of the regular builds and may not have included testing against every special build as well. If you are running a special build, be even more cautious in upgrading than you would normally be.

Why read the Release Notes?

Previously in this document, it was recommended that before upgrading from one version of the firmware to a more recent one that the Release Notes be read. To give an indication of how important it is to read the Release Notes, we have provided a sampling on the next page of some of the possible issues that may have to be dealt with upon upgrading.

To offer some clarification on the contents of this sampling, some of these issues were and are unavoidable because of the nature of the configurations of the FortiGate devices and the networks they were in. The reason for reading the Release Notes is to make sure that users are prepared for changes or potential outages that may occur so that the affected parties can be forewarned and the issues can be dealt with in a timely manner.

Supported models

While it is not necessarily an upgrade issue, one very good reason for reading the Release Notes is to verify that your model of FortiGate is supported by the firmware. The reasons for a particular model not being supported can be:

1. The hardware was out of development when the firmware was released
2. The hardware was developed after the firmware was released
3. The hardware doesn’t have enough resources to run effectively using the firmware
4. Only some models were included in the development of the firmware.

There are some instances where a model may not be supported by only some builds of the firmware. But just because a model appears to go out of support does not mean that the situation will continue moving forward. It’s worth checking to make sure.

For example, the FortiGate/FortiWiFi 80C and 81CM were not supported by the  5.4.0 firmware. There is no version 5.4.0  firmware for these models. However, these models were brought back into the supported list for 5.4.1. This presents a slightly different problem than normal for the people using the upgrade path tables as some of those paths could refer to upgrading to 5.4.0 before upgrading to 5.4.1 or one of the later versions of 5.4.

The solution is relatively straightforward. Use the 5.2 table to upgrade to the latest version of 5.2. From there, it should be easy to then use the 5.4 table to upgrade to whatever is the latest version of 5.4, effectively skipping right over 5.4.0.