Upgrading database to 3.0 produces a "fatal error"

I try to upgrade ojs after turing “installed” off in config.inc I receive this
Fatal error: Cannot redeclare class Plugin in … /classes/plugins/Plugin.inc.php on line 19
and I got no idea what to do.

when turning “installed” on I get a “DB Error: Unknown column ‘context_id’ in ‘on clause’”

Any idea how to fix this?


When upgrading from 2.4.x to 3.x, it is important to work with a new copy of the codebase. Don’t try to drop the 3.x codebase overtop of the 2.4.x codebase.

Keep your original 2.4.x install untouched until you are happy with the upgrade… this gives you an easy “revert” if you get in trouble. Install the 3.x source to a new location. Copy the database, and copy the file structures of files_dir, public, and config.inc.php to be available to the 3.x source. Then run the upgrade script from the 3.x source path. If successful, replace the 2.4.x install with the 3.x install.