My current forum version is 2.15. I have download the full PHP version of 2018.4.11. However, I got the error message "An error occurred trying to update the database
Table 'phpbb_admin_nav_module' already exists" while trying to install the PHP new version.
Here are the steps that I did:
1) backup my database.
2) backup the whole old forum.
3) delete the old forum files on my server.
4) copy the newer version into my server.
5) change mod for .config file.
6) run mywebsite.com/install/install.php
7) fill in the old database info.
---> give me the error "An error occurred trying to update the database. Table 'phpbb_admin_nav_module' already exists"
However, If I try to connect to a new database, the installation is fine, but it will give me error "can't recognize one field in php-categories table." in the restore database step.