The translated source doesn’t give away any specific information about where the file came from. However, those who have tested the file suggest that the firmware is official and that all of the important parts for a daily driver are working fine. WiFi, network data, NFC, Bluetooth and all the sensors appear to be working correctly. Although, some of the system messages appear to be in Chinese, as this is where the source originates from. That being said, small bugs may still appear as this is unlikely to be Samsung’s final build before release.
The file will apparently flash on several versions of the Galaxy S4, including the GT-I9500, GT-I9502, GT-I9508, and the GT-I9508v. However, it does not work with the GT-I9505, which is powered by a Snapdragon 600.
If you fancy testing it out, make sure to perform a backup first, as data is wiped and you never know what may go wrong. You can grab the download to flash with ODIN from the XDA forum. Be sure to read through the topic for extra instructions, as installing a recovery and gapps is a bit of a hassle just to grab some official firmware a little early. The polished nature of this leak suggests that Samsung may be close to pushing out an official version in the not too distant future anyway. Previous reports had suggested early 2015, so it may just be worth waiting.
Let us know your thoughts if you test out Lollipop on your Galaxy S4.