Cannot Upgrade emoncms from version 8.3.5 to version 9

I’m trying to upgrade emoncms to version 9, but I cannot go over database update.
When I go to http://localhost/emoncms/admin/db page and I click on “Update & check” button I get only a page with “Update database” title and no list of changes to be performed ad I cannot do any action.

Can I activate some log to understand the reason of the failure?

Thank you,