The provided information is not sufficient to provide any help in resolving the issue. A complete and detailed description is required for the support team to get a clear understanding of the problem. Explain what you do, what are the results you expect to get and what you actually get.

Make sure you follow the documented upgrade process http://mantisbt.org/docs/master/en-US/Admin_Guide/html-desktop/#admin.install.upgrade
If that fails, provide details about the error(s).

I need to upgrade the version of my mantis to 2.23. In the change log : https://www.mantisbt.org/bugs/changelog_page.php We can see at the 2.23 version : "This feature and maintenance release includes a schema change. Do not forget to upgrade the database as documented in the Admin Guide."
But when i upgrade the databse on "/admin/install.php", the tables name change. And i can't connect with my credential or the bug is not present. For example actually in the 2.5.1 version the user is stored in table mantis_user_manter and now in the 2.23 version is stored mantis_user_table. The name of many other table have changed. Do you have solution for migrate data to the right table.
Thanks

I managed to solve my problem. I first updated to version 2.22.22 and then to version 2.23.
Regards,