Hi!
The https downgrade is still working, as any other attack it has its own limitations but it’s definitively working. We can try to debug the issue, just open a new thread.
Yes, Xarp is only available in unofficial website but there’s nothing we can do about it, unfortunately there’s no good alternative for it.
Which exploit are you talking about? Also you can open a different thread so we can help to debug the issue.

Greetings!
Diego