404 error when upgrading ojs 2.4.8 to 3.0.0

Hi everyone, I have an ojs installation in version 2.4.8 and I deleted all the files except the public folder and the config.inc.php file and pasted all the folders from version 3.0.0 and ran the updater and it gave this error:http://ojs.homologa.ufpr.br/index/install/installUpgrade

Hi @JUCIO_GABRIEL_ARAUJO,

This doesn’t answer your question directly, but, if you haven’t seen it already, you may want to have a look at our guide for updating from OJS 2 to OJS 3 here: https://docs.pkp.sfu.ca/upgrading-ojs-2-to-3/en/introduction

-Roger
PKP Team

I managed to solve it, but after solving the problem and clicking on update system the software returned this error > A database error occurred: ERROR: null value in column “assoc_id” violates not-null constraint DETAIL: Failing row contains ( 1, null, null). how can we solve?