Samsung Galaxy S4 LTE model number I9505 seems to be the first in line to receive the official Android 4.3 Jelly Bean OTA Update. This looks like it should happen soon as a test build of the I9505XXUEMI8 Jelly Bean firmware has been leaked for this particular device.
You might thing that since this is a test build, then there is still a lot of work to be done on it, but it seems like this Android 4.3 XXUEMI8 firmware for Galaxy S4 LTE runs smoothly and there are no major bugs reported. You can also flash it on your device using ODIN, but we advise you to do that only if you’re an advanced user.
Since this unofficial build of Android 4.3 test firmware for Galaxy S4 I9505 is in its testing phase at Samsung and it has the test build set to September 20, then we can expect Samsung to launch the official OTA Update firmware by the end of this month or early November. The guys at SamMobile also tested this release and it seems like the Android 4.2.2 lag and other small bugs are now gone, while the whole ROM is faster than ever.
Besides the Android 4.3 Jelly Bean build number changed to XXUEMI8, you will also notice the presence of Samsung Know and Samsung Wallet, Reading Mode was added for you to be able to read text much more easily on your phone’s display. Other changes have been applied on the user interface.
If you want to flash the Android 4.3 XXUEMI8 test build on your Samsung Galaxy S4 LTE I9505, then you should follow the instructions listed here. After you update make sure to tell us in comments which are the best features and improvements added by this test firmware.