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 the International Galaxy S4 I9505 LTE. Follow on to get the instructions about how to update Galaxy S4 LTE to Android 4.4.4 based CM11 M9.