Potential FortiOS Upgrade Issues: Combination of Variables Issues

Combination of variables that produce unexpected results

Every now and then a specific combination of variables will produce a side effect that is completely unexpected. Most of the time, these side effects may not even be noticed but occasionally there can be some loss of functionality.

Example: Link aggregation
One such example of this occurs when upgrading a FortiGate 600C from 4.3.18 to 5.0.11. If the FortiGate is configured to use Link Aggregation Control Protocol and an upgrade is done directly from 4.3.18 to 5.0.11, the VLANs under LACP will disappear and WiFi mesh devices show up below it.

In order to prevent this from happening an upgrade to 5.0.7 needs to occur before the upgrade to 5.0.11. The reason that this path is not part of the table, is that this situation refers to only 1 model and with a particular configuration.

Example: Application Control
When upgrading from 5.0 to 5.2, there is a curious time delay on a side effect involving Application Control profiles. If you have an Application Control profile that has some categories included, as well as some individual Application Control signatures, and you upgrade from 5.0 to 5.2 everything will work as it did before. There is the slight side effect that you will no longer see the individual signatures in the GUI, but the functionality will still be there. The problem arises when the profile is actually edited. Editing the profile removes the individual signatures. The only way to correct the error is to manually enter them in again.