Já acessamos esse documento e encontramos a seguinte informação
ote: Before upgrading your installation, perform a complete backup of your
data files and database. If the upgrade process fails, you will need to recover
from backup before continuing.
If you are using PHP Safe Mode, please ensure that the max_execution_time
directive in your php.ini configuration file is set to a high limit. If this
or any other time limit (e.g. Apache's "Timeout" directive) is reached and
the upgrade process is interrupted, manual intervention will be required.
Upgrading from OJS 2.0.x, 2.1.x, 2.2.x, or 2.3.x