[Q] Cant update android

I have a GSS4 i9505.

it is unrooted/100% stock, as I do not wish to muck around with any of that just incase the worst happens and it needs to go back to repair again i'd feel safer knowing that its device status remains Official.

about 6 months ago it went back to optus for repair as the battery had swollen leading to problems.... when i got it back the repair slip said, replaced battery, tested phone - no issues, updated to latest firmware.....

which i thought to be weird as i thought i was on 4.2.2 already.

anyway... Optus has now finally released their version of android 4.3... except when i go into phone settings and click update.. it says i am already running the latest version... when i connect to Kies via USB it says "your devices current firmware version is not supported to update firmware via Kies"

in Kies i get

PDA:MDE - PHONE:MD8 - CSC:MD6 (OPS)

when i do *#1234# i get
AP: I9505XXUAMDE
CP: I9505DVUAMD8
CSC: I9595OPSAMD6

i have no idea what any of that means

would i be correct in assuming that since i have never mucked around with roms,etc and the only time anything like that has happened was when it went back to optus for repair.... that optus stuffed something up and that why i cant update ?

cheers.... i had thought of odin but as mentioned about, figured that it'd probably void warranty which i would like to avoid as knowing my luck the screen would all of a sudden stop working and i'd have no way of re-official'ing it.

might just have to take it into optus and get them to update it themselves.