by Derek Chirnside.
Rafael, if you mean 'Restore from 1.9 into 2.4 WITH user data', I have wondered this also. Recently Tim has given an answer here: https://moodle.org/mod/forum/discuss.php?d=227816#p989743 in short, it's just too complex, and no-one is willing to spend our precious programming hours on this.
-Derek