Difference between string[80] and string in Delphi 7 and Delphi XE4

Difference between string[80] and string in Delphi 7 and Delphi XE4

I am migrating a delphi 7 application to delphi XE4. In Delphi 7, some
variables are declared like this:
var abc : string[80];
While migrating this code, I am changing above code declaration as
var abc : string;
As per my understanding, string[80] is ansistring and string is unicode.
So, is it right way to do it?
I am following the below link from stackoverflow:
Convert Char into AnsiChar or WideChar (Delphi)