I tried to update a Drupal 7 site to the latest version. The old Drush update doesn't work and it throws an error about a unknown engine type output format.
I tried to delete the web folder, extract Drupal 8 files, change the database connection settings to use the old database, and call update.php. It doesn't work, and it throws errors about MySQL encoding.
I tried to install Drush 9 to upgrade core, but it keeps complaining about the composer.json file.
I tried to install Drush 8, but it shows more errors.
How am I supposed to update an old Drupal installation to latest core version?