Cannot update from 13 to 15 manually

I use nextcloud on a webserver ( I want to update from 14 to 15. First I downloaded version 15 and installed it in a new directory. Then I copied the config file and the /data folder into the new directory. When I now call nextcloud I get an update screenshot that I can update to version 15. If I confirm the button, I get an error message that the update failed (Major Update is not supported). I don’t understand the problem!

Did you first update to the latest 14.x version?

What exactly does „installed it“ mean? Did you just copy the files in a new directory, or did you install Nextcloud 15 so that you did login to the new version before copying config.php and the data-folder?

Which version is mentioned in your config.php from your old installation?

Sorry, I’m currently using version 13 (not 14). So I took the following steps.

  1. download version 15
  2. unpacked and uploaded to server in new directory
  3. config file and data directory copied from old directory to new directory
  4. renamed old directory
  5. new directory renamed
  6. nextcloud called
    Now the Updater screen appears. I click ok.
  7. i get an error message, update not possible