OJS fails to upgrade from to

Hello smart people.

I am trying to upgrade OJS from 3.1 > 3.2 > 3.3 > newest at the time, but I fail at upgrading it to
I downloaded from the site, created new DB and imported existing DB on it, I copied .htaccess file, public files and config.ini.php and set installed to off in it. When I click Update OJS on the website it thinks for a good minute and gives me this msg:

Errors occurred during installation:

  • A database error has occurred: Duplicate entry ‘13-en_US-subject’ for key ‘email_templates_settings.email_settings_pkey’

Hello @MR.Pillow ,
According to the documentation, the config.inc.php file should not be copied, you only have to edit it (DB, user, pass, etc) since it changes between versions.
Check that the tables have the InnodB engine.

Remember that with every failed upgrade attempt, you need to restore the database again.

Thanks for respond, could you provide a link to documentation? The link I used says that I need to copy config.inc.php file to new ojs folder

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