About the Maintaining my Dolibarr category

Get help on updating Dolibarr to a newer version, migrating a Dolibarr instance to a new server, backup and restore operations (files and database ) and more generally, everything related to the configuration and system maintenance of the machine hosting your Dolibarr instance (cron, permissions, etc.).

Update Dolibarr v13.0.3 to v14.0.3.
I installed Dolibarr v13 on a Debian 10 buster OS with php8 and Mariadb.(Virtual host)
No problem with installing the sotftware and getting Dolibarr working.
I’m trying to upgrade v13.0.3 to v14.0.3 following the dolibarr update instruction.
I have a usr/share/dolibarr dir with a scripts and htdocs directory. I download the dolibarr-14.0.3.zip file in the usr/share/dolibarr. Unzip it and copy the dolibarr-14 directory to the dolibarr. Remove the lock file in /var/lib/dolibarr/documents and open dolibarr in a browser then the install page is shown but I don’t get the upgrade option v13 - v14 only new install. I’m sure that my lack of experience with dolibarr is part of the problem but is there someone who can give me a hint how to solve this problem?