Upgrade from 3.9 to latest version

Hello everyone, i have a question for you expert in  the field
My shop is running 3.9 version. I'd like to upgrade it to the latest (i believe its 4.40)
What is the smartes way to move?
U suggest to make a fresh installation of the 4.40 and then update each table in sql with the old one, such as orders, clients, etc?
Or theres a better way to upgrade it? i dont know if i have to go through each version or there is a way to make a single update from 3.9 to 4.4

Im quite new so i'd like an advice from you.
What you whould do in this situation?
Thx a lot

You will need to upgrade the database, with scripts to get to 4.30 first.

So, (very important!!), backup your database, and all files.

Then, in this order, upgrade your database to 4.30 using scripts:
3.9 > 4.00
4.00 > 4.10
4.10 > 4.20
4.20 > 4.30

From version 4.40 you don't need SQL upgrade scripts. The upgrade is performed automatically with migrations (during the first application start). So when you upgrade from 4.30 to 4.40, you don't need any scripts.

Also, as go through each upgrade step, if you have any third-party plugins, make sure you run their own upgrade scripts too.

Here's a link to the docs:
https://docs.nopcommerce.com/en/installation-and-upgrading/upgrading-nopcommerce.html

Hi, this may be a dumb question, I'm new on this as well. To upgrade from one version to another(my current is 3.7) I know I have to follow next steps:

- Remove all files from the previous version except JSON files in the 'App_Data' directory such as dataSettings.json (Settings.txt in oldest versions), plugins.json (InstalledPlugins.txt in oldest versions), appsettings.json, move them to the safe place.
- Upload the new site files (get the latest version here).

My question is, do I have to remove and replace ALL FILES of the site, or just the ones contained in APP_DATA folder?

Thanks in advance.