Here is the official CM11 M9 custom firmware from the team CyanogenMod to update your Samsung Galaxy S4 LTE to the Android 4.4.4 KitKat. Designed by CM, the custom firmware packs quite a ton of features and updates. Here is the complete changelog as posted on the CyanogenMod official website.

CM 11.0 M9 changelog:

* Themes support for additional UI elements

* Heads Up Notifications – Bug Fixes

* Lockscreen – Allow doubletap to sleep when using secure keyguard

* Torch – Improve performance

* Safe Headset Volume – prompt when interfering with 3rd party device (Jawbone, Square, etc)

* Center clock support

* Quick Settings – respect locale changes on additional tiles

* Proximity Wake-Up support – prevent accidental wake-up of device by checking to see if proximity sensor is blocked (eg. Device is in a bag or pocket).

* Spam notification filtering – Set notifications to auto-ignore based on content (perfect for those pesky games that want you to ‘Save 20% on our new game’). Long-press offending notification to set as ignored; manage in Privacy settings.

* Settings Search – Additional improvements and highlighting

* Data Usage Info – Add support for CDMA devices without sim cards

* Bluetooth – Add additional A2DP profiles

* Bluetooth – Disable AVRCP 1.5 by default (fixes various car unit compatibility)

* Email – Fix saving attachments to storage for POP3 accounts

* Translations (Thanks CM Crowdin Team!)

* Account for Play Services induced wake-locks

* Fix encryption on some LG Devices

* Dialer – add support for Korean and Chinese to smart-dialer

-Important:This update is valid for following Samsung Galaxy S4 variants:flteatt, jfltecan, jfltecri, jfltecsp, jfltespr, jfltetmo, jflteusc, jfltevzw, jfltexx, and theInternational Galaxy S4 I9505 LTE. Follow on to get the instructions about how toupdate Galaxy S4 LTE to Android 4.4.4 based CM11 M9.

Prerequisites to update Galaxy S4 LTE to Android 4.4.4 CM11 M9:

Create abackupof all important data in your Galaxy device.

Download and install USB drivers forSamsung Galaxy S4in your computer.Enable USB debugging option by pressingMenu>Settings>Applications. Navigate and tap onDeveloper Optionsto ensure thatUSB Debuggingis enabled.Make sure that recovery tool likeClockworkMod recoveryis installed.Ensure that your Samsung Galaxy S4 LTE carries more than 80% of charge.

How to update update Galaxy S4 LTE to Android 4.4.4 CM11 M9:

Files required:download theCM11 M9 Android 4.4.4 KitKatcustom firmware fromhere; also download theGoogle Apps. Save both files on PC.

Here are the steps toupdate Galaxy S4 LTE to Android 4.4.4KitKat based CyanogenMod 11M9:

Connect your SamsungGalaxy S4to your computer using USB cable and copy the downloaded files to the SD card of your Galaxy device.Disconnect the connection with PC and turn your Galaxyoff.Boot in to custom recovery mode: press and holdVolume Up, Downand thePowerbuttons simultaneously untilSamsunglogo shows up. Leave the keys for half a second and hold again. UseVolumekeys to scroll andPowerbutton to select -alternatively you can useQuick Boot appto reboot your Android device in recovery mode.Now perform Nandroid backup of your current ROM: selectBackup and Restore>Backup. Go back to main recovery menu after backup process is done -very important step to restore back to current OS.Data wiping tasks: selectwipe data/factory reset>Yes. It will take a few minutes; once done, selectwipe cache partition.Next tap onAdvance>wipe Dalvik Cacheto wipe Dalvik cache data too.Selectinstall zip from sdcardfollowed bychoosezip from sdcard. Locate the Android 4.4.4 KitKat based CM11 M9 custom ROMfile copied earlier and select it. Tap onyesto confirm installation and wait for the ROM installation to be completed.Once installation process is finished successfully, repeat the above step but chooseGAppsfile instead to install the Google apps package on your Galaxy S4 LTE.Return to main recovery menu now and selectreboot system nowto boot up into the latest CM11 M9custom ROM forSamsung GalaxyS4. It will take a bit of time during the first boot, so kindly be patient.Ta da! This was how to update Galaxy S4 to Android 4.4.4KitKat based CyanogenMod ROM!

How to restore:If you want to return to previous OS on your Galaxy S4 LTE, boot intorecovery, selectbackup and restorethen restore your previous ROM by selecting it from the list.