All Samsung listed in the update v1.2.0.4 (see our change log) are supported no matter the version of your firmware, but as long as not using the "Device Unlock App" (MetroPCS & T-Mobile USA Only)
For any other Samsung Cell Phone, unfortunately these are not supported by our method, however it's possible to downgrade your phone.
We recommend you to downgrade your phone BEFORE ordering your license, as we do not provide support for downgrading.
Since it's permanent unlock, after unlocking you'll be able to upgrade your phone again to the latest version of Android !