Upgrade 9.1.8 to 10

Please help. I copied the folder “data”, and the config folder,
installed a cloud, loaded the database, loaded the folder “data”
But when I try to enter I see this

Update required
It is possible that your instance may contain many files and / or users. To ensure a smooth upgrade process, use the update via the command line (occ upgrade).

When I try to find information in Google, I’m sent to non-working pages
for russia there is no data

Please input your English.
Если ты русский, помоги по-русски

It's very bad that there is no normal documentation.
If anyone has encountered the problem of updating from 9 to 10 versions, here is the solution to the problem

sudo -u www-data ./occ maintenance:mode --on
sudo -u www-data ./occ config:system:set mysql.utf8mb4 --type boolean --value="false"
sudo -u www-data ./occ upgrade
sudo -u www-data ./occ config:system:set mysql.utf8mb4 --type boolean --value="true"
sudo -u www-data ./occ db:convert-mysql-charset
sudo -u www-data ./occ maintenance:mode --off

@Roman_Anderson running ./occ upgrade on terminal/ssh was the correct thing to do - this is what the message in the browser told you :wink:

From my point of view there is no need to convert your mysql database to mb4 in order to allow a successful upgrade. But it doesn't hurt either :wink: