> with all functions working correctly

do you mean (1) "functions" of the HTTrack tool? or (2) functionalities on a
website?
if (1):
I don't know, try it out and see if you are pleased with the result. But a
software project, which hasn't gotten any recent updates, does not mean it is
not functional anymore. Infact, it could be also the opposite: it reached a
maturity level and therefore less and less things were tbd over the years.
There are other examples of specific software packages, which haven't gotten
any updates in years, but run super stable.

if (2): by the nature of this type of tool category, it is simply impossible
to create a 100% clone. These type of tools create snapshot copies in a static
manner. Especially server-side functionalities can not be copied. If something
is executed through client-side JavaScript (as example), it may or may not
work. But latest when a server interaction would be part of a function on a
website, this will not work.