Once u root your phone, I believe u cannot update via OTA... It will always tell u that its up to date... Moreover Kies won't work either....
Your best bet is to download the latest firmware and flash it thru CWM or Odin...
Sent from my GT-I9500 (Hassan Khalid Malik) using Tapatalk 2
Hassan Khalid Malik
★★★OMEGA ROM Team Member★★★
Samsung Galaxy S4 I-9500 - Omega Rom 18, Perseus 18 Alpha, Philz Touch Recovery 6, Xposed Framework & Custom init.d Script -
Samsung Galaxy S3 I-9300 - Omega Rom 56, Googy-Max2 2.1.7, Philz Touch Recovery 6, Xposed Framework & Crossbreeder 7 -