I had to warranty my phone back to TMO when it became increasingly unstable running 4.3 and I had every major problem listed. I had not changed any apps that ran under 4.2, nor added any new, but it kept freezing, rebooting sponateously, unstable wifi warning, crappy battery life (when it was great before I went to 4.3) etc. I am wanting to know if I install the update for Kitkat (s4 M919) will it fix these issues? If it doesn't fix the battery life issues, and the constant reboots, I am seriously considering more drastic measures.
So...does 4.4 work, or not?