So the deprecated message is just a naming convention thing. In class definitions instead of using:
class WA_AltClassIterator {
var $DisplayIndex;
var $DisplayArray;
function WA_AltClassIterator
you now have to use:
class WA_AltClassIterator {
var $DisplayIndex;
var $DisplayArray;
function __construct
It used to be that a function inside of the class that used the same name as the class would be treated as a constructor. They are deprecating that syntax and forcing you to use the function name __construct for your constructor function within a class.
I'd just turn off deprecated messages and ignore that one. It will still be supported until php8 and we are updating those in the next release.
The SecurityAssist authenticate user Server Behavior uses standard mysqli and isn't php7 ready. We already have the replacement function in the MySQLi server behaviors and in the next version the Security Assist wizard will use that one instead. For now you would have to reapply the server behaviors manually.