Re: Upgrade path 5.2.10 to 5.6.5 or 5.2.10 to 5.4.9
I think (not sure) the tool is showing just one possible upgrade path simply based on the fact that each step of the upgrade is supported, without considering in what kinds of bags are with the version, which might break previous config depending on the features configured and used.
Based on the assumption, I think (again) your educated discretion is necessary to modify the entire path from the one given by the tool to avoid some particular upgrade problems, by checking each step using the same tool since that information is no longer provided with release notes.
At this moment, at least I don't have any problems deploying 5.6.5 IF we didn't have zones with the parent and vlan sub-interfaces. Practically it's impossible to upgrade those FGTs in the field. However, that's the only issue holding us from upgrading the whole fleet of our FGTs. Others in the forum might have different opinions (likely).