What are requirements for an update?

[emlaraal]

I have samsung galaxy s4. The things is, my friend has it to, but hers is updated . It has brand new design so it must be this new version of Android (lollipop).

I cannot update mine whatsoever, I tried to update it manually but it says that it is updated.

I am not a teach expert and I cannot find the answer on my question which is "what are requirements for an update on smartphone" , in my case galaxy s4...

 

[cpaight]

Usually it's a holdup from the carriers....are both of you on the same network? If not, that's likely the reason.

 

[kyleiniowa]

Sometimes even the same carrier rolls out the update in waves, my family is all on the same plan and an update wasn't available at the same time.