Dear admin and Friends
I attemp to upgrade OJS from 126.96.36.199 to 2.4.8. Due to OJS version is quite old, I just upgrade step by step or one version higher 2.3.6 to 2.3.7. I have problem while upgrading, there is error notification like this DB Error: Duplicate entry ‘customBlockManager-1-1-0-0’ for key ‘versions_pkey’ I don`t know why and how to solve that ? please, the solution.