Update for att s5 on tmobile service? So I got an att galaxy s5 that is being used on tmobile service.  Am I out of luck as to getting either the att 4.4.4 update or the tmobile lollipop update?  Checked through settings and version is 4.4.2 and shows as no new update is available for att and I do not see an option for tmobile.
Have you rooted your device? If you have rooted your device you wont get any update. 
If not rooted then you can try by installing Kies to your PC and then try updating through PC.