I have tried to upgrade using softaculous. Everything seemed to go fine except that many things don't work. For example attempting to put some items into an image slider bring up and error that a column in the sql table does not exist.
Attempting to add a link to a feature (nice addition that) does not work because the link is not saved.
I have no problems if I install a dummy version of 5.7.3.1 in a subdomain - it all works fine.

It would seem that my sql table and the new one is not compatible. Is there an easy way to fix this without re-building the site from scratch?