Upgrading old Pixhawk firmware from 3.4.2 to 4.5.7

Hi. I’ve just started getting back into building and flying quad copters after doing nothing for 8 years. My old TBS Discovery has a Pixhawk running v3.4.2. I’m leaving it as is for now until I can at least get it flying and I relearn all the stuff I’ve long forgotten, but I would like to update the firmware sometime soon.
It’s taken me a few days but I’ve connected Mission Planner, confirmed my radio configuration (Taranis FrSky), and finally got it to arm (not yet flown).
Is there anything I need to be aware of before taking a big jump in firmware versions or should it all go OK?
Thanks.

Incremental updates are almost always non-issues. But updating 10 years at once? I think you’d best be served starting fresh, as if it’s a new build. Take some notes on your existing tune and parameters, but I’d almost place a bet that those notes will be nearly useless due to the massive changes in the recent and not so recent past.

Thanks for the advice. I might just use it as a ‘re-trainer’ (I can’t even remember what half of the peripheral components do!) and then undertake a new build. I expect everything on it is pretty ancient technology now!

If it’ll run 4.5 firmware (and it sounds like it might), it’s worth a try to revive it with the modern features. But I think it’s a “new build” mentality vs a simple update.

New build, new tools.

This time use the ardupilot methodic configurator software to configure it.

It removes the guess-work from the equation

Hello, I am in the same situation after 6 years I am assembling a fixed wing drone and the new version 4.5.7 does not ARMING
I performed all the steps ACCEL CALIBRATION
COMPASS
RADIO CALIBRATION
I worked on all the ARMING parameters and I did not succeed
I installed version 4.3.3 and it ARMING but it does not allow me to adjust AIRSPEED CRUISER or the NAVIGATION ANGLES parameters
I would like to work with the latest version
Can you help me?
Thank you very much

Use the ardupilot methodic configurator software to configure it.

I saw that they are working on extending it for arduplane
Anyway I’ll see if I can solve my problem
Thank you very much