Question can i downgrade from 4.4 to 4.3?

hi fellow xdaers,

got a question on my i9505. i have installed this rom for a while and due to my local telco running only 4.3, they mention that my phone is grey unit and they do not want to warranty it.

i'm wondering if i can re-flash back to its original 4.3 (telco) rom using odin without issue so that i can bring have it repair under warranty.

any gotchas should i look out for?

thank in advance.
Current: Xperia T2 Ultra (D5303)

Prev Phone:
Galaxy Note 2 N7105
Samsung Galaxy N7000
SGS2 (frankenstein) - PDA: XWKK5 | Modem/phone: XXKI3 | CSC: XEUKH2
HTC Desire - ROM: InsertCoin CM7 HBOOT/STOCK 1.0.8
bravo pvt4 ship s-off, hboot-0.93.001
radio-, CWM-Alpharev recovery v

Previous Tablet -
Acer Iconia A500 - Lightspeed_4.3[ICS4.0.3] ROM)
Acer Iconia A501 - Moscow's Alexandra III Rev 1.1
Samsung Galaxy Tab P1000T - OverCome GB ROM