2
Both register.php and include/registerform.php have changed from 2.0.7.3 to 2.0.10.
If I were going to use the hack in 2.0.10 (or the newest version 2.0.11), I would compare the hacked files with the unhacked 2.0.7.3 files, to see (and understand) what the differences are. Then I would apply those changes, updating them if required, to the 2.0.10 (or 2.0.11) files.