Problem seems to be the update PHP version, not the database.
If you have a new empty 23.1 installation, you should drop all tables of the egroupware
database and then install the database dump from the old system. Go to setup (upper login, use setup user admin
credentials) and update the database from 17.x to 23.1.
After that you probably need to change some of the configuration settings like directories and webserver-URL.
You should also copy or rsync /var/lib/egroupware/default/files
for your old installation to the new one.
An other alternative is to buy some support, and we (EGroupware GmbH) do the update bases on the MySQL dump for you.
Ralf