Password hashing method needs upgraded.
Steps to reproduce
Added missing include in password_funcs.php to use new hashing.
The above was not the issue with logins. I am committing a fix for that issue now. See issue
Thanks. Still a bit rusty. forgot to commit them as usual. Coming later today.
I think you missed adding
require DIR_WS_FUNCTIONS . 'password_hash.php';
Not your fault. I broke the admin session handling with the mysqli update. I have a partial fix that allows logins to work but there are still some session handling issues in the admin (namely on the login screen itself and also categories.php).
I broke a few other things with the mysqli update as well (installer is not quite working right - some tables were not installing for me - I also have fixed that by updating the installer to use mysqli too).
The easiest temporary fix for the admin is to revert includes/functions/database.php to the previous version in your local installation - it fixes all the session issues in the admin.
I will commit the partial fix today so you can get back into the admin panel.