Galaxy 3 KitKat update

[hybucket]

I was just informed that my ATT Galaxy 3 has an update. I assume it's for the 4.4 Kit Kat. I have two S3s. ONe is up to date with 4.3, the other is still on 4.0. Has anyone had any experience in updating 4.0 to 4.4? I"m concerned that the 4.0 is so far behind, it might screw up the S3. I know even smaller updates have screwed up my contacts and other stuff on the phone.

 

[B. Diddy]

Not sure why one of them was still stuck on 4.0. Was it rooted, I wonder? Or was it a phone from a different carrier that was ported to AT&T?