Is a new installation of NC15 compatible with old NC10 files

Good Day!
Until now I have an old version of Nextcloud 10.0 working.
Now I want an upgrade.
Unfortunately upgrading with the updater is not working well in my NC-Version.
So I want to install NC 15 and shift all my old files and directories.
(I have to do this via ftp. My provider is All-inkl in Germany).
Before starting I have the following questions:

  1. Is it possible to upgrade directly from NC10.0 -> NC15 by a new installation of NC15 and shifting the old files(directories)?
  2. Are there any further instructions for this specific question: Upgrading by new installation NC10->NC15 via FTP.
    I see this one:

Major upgrades are not supported so far. They think about it and I’m not sure if it could work, but I’d guess for more recent versions. And I wouldn’t risk it at all on a hosted environment. And if you have full manual access, you can run all these upgrade quite fast.

If I know that there are problems with a specific hosting environment that the upgrades risk to fail and I planned such a larger migration, I’d migrate the whole setup in a virtual machine, run the upgrades and migrate back. All the upgrade stuff should be carried out on the database, so ideally you’d only need the config.php and a database dump.