My Experience

Use the CM 11 KitKat Nightly if you want to run a stable AOSP Android 4.4 on your T-Mobile Galaxy S4 phone.
This guide is destined to be used by users who want to tinker with their devices and get rid of all the TouchWiz and and all the other bloatware that Samsung loves to add to the overall UI whenever a new device is launched. More info about CM 11 Nightlies can be found at the CyanogenMod blog here.
Before starting the installation you will first need to take a look at the guidelines below:

• Use this post only with the T-Mobile Samsung Galaxy S4 phone.
  - don’t update any other Galaxy S4 variants with the zips that you find in this post, as you will end up bricking the device’s firmware.
• your Galaxy S4 T-MO has to be rooted, factory unlocked and running the latest CWM Recovery version.
• make sure to create the ‘NANDROID ROM Backup’ for the OS build that is currently installed on your device.
  - this step is listed in the tutorial and you shouldn’t skip, as it will full and working restore point for your Galaxy S4 T-Mobile.
• ‘factory reset’ needs to be applied every time a new custom ROM is installed on your device.
  - this step is found in the tutorial, don’t skip it.
  - factory reset wipes data from system partition, but not from internal nor external sdcard.
  > factory reset can be skipped only in case your device already runs on a previous and official CM 11 Nightly ROM.
• data from installed applications can be backed up using the Helium tool — Google Play Store link here.
• backup SMS and APN Internet Settings using the following tools for Android phones: SMS backup & restore | APN Settings Backup & Restore.
• sync all your Contacts info with the default Gmail account that you’ve assigned for your device.
  - a guide can be found here in case you don’t know how to sync such data.
• enable USB Debugging from the Developer Options menu.
• read the entire post, don’t skip any steps and make sure that you know what you’re doing.
• if you cannot complete the guide, then you should ask for more help in comments.
• check the phone’s battery power level and make sure that it is over 50%, so that the phone won’t switch off in the middle of the installation.
• this is a guide for advanced users, do not blame us in case you lose any data or brick the phone.

Now that you know all of the above, continue to the tutorial part of this post.

How to flash CM 11 Nightly KitKat custom ROM for T-Mobile Galaxy S4:

1. Download the CyanogenMod 11 Nightly zip from here.
   - download the latest build available not the older ones.
2. Download Gapps zip for Android 4.4 custom ROMs from here.
3. Use the USB Data Cable and connect your phone to your PC, then move both zip files to your phone’s internal storage.
   - disconnect the phone from PC when the files are transferred successfully.
   - make sure not to unzip the archives.
4. Power off your Galaxy S4 now.
5. Next, boot the T-Mobile Galaxy S4 in CWM Recovery Mode.
   - here’s a guide that teaches you how to boot custom Recovery.
6. Create a full NANDROID Backup for the ROM that is currently installed on your SGS4:
   - select ‘backup and restore’ option, rename the file and save it on your phone’s internal storage.
7. Now you can “Factory Reset” your device:
   - select ‘wipe data/ factory reset’, then confirm the process.
8. Now you can finally install the CM 11 Nightly ROM:
   - select ‘install zip from sdcard’, then ‘choose zip from sdcard’ and find the CM 11 Nightly zip.
   - confirm the installation and don’t press any buttons until the process is complete.
9. When the ROM is flashed, select once again ‘choose zip from sdcard’ and flash the Gapps zip.
10. After both zip files are flashed, get back to the main custom Recovery menu.
11. Reboot your phone now in normal mode.
    - the first boot process of CM 11 Nightly takes several minutes to complete, don’t press any buttons until the process is complete.
12. Enter / Create your CyanogenMod account or use your Google Account details in order to take control over your smartphone.

>Note: if the first boot doesn’t go past the Samsung boot animation after ten minutes or the device enters into a boot loop, then you should repeat the entire tutorial without skipping any steps.
I hope that you’ve managed to complete the tutorial and flash a brand new custom ROM for your Samsung Galaxy S4 T-Mobile. If you cannot complete the guide, then you should ask for more help using the comments field below.

The ‘Call Logs Backup & Restore’ is a free Android application for smartphones that allows users to backup call logs directly on the device’s SD card. Also, you can create a special folder that resembles ‘call log backup restore’ folder name.
This application has support for viewing all the backups straight from its interfaces. It comes with support for automatic scheduling backup and you can set your own customized folder where to save the call logs. All the backup files are saved as .XML on the Android’s SD card. It can be easily downloaded from Google Play Store and if can’t understand how to use it, then please feel to ask for help in our comments section.
Call Logs Backup & Restore has support for up to 500 calls and you can easily restore all of them to your smartphone. This small Android app will help you backup and restore the call logs for your Android phone after you’ve update, rooted or flashed the firmware of your device. It is extremely easy to download and you can save it on your Android smartphone by clicking here. Remember that the default location where a backup is saved is the /sdcard/CallLogsBackupRestore directory. As I’ve told you already, you can easily specify the Backup folder where you wish to store the call logs of your Android smartphone.