Process to update the Samsung S4 i9500 manually to Android 4.3
Most users will use the Kies software to update, but it could be that you want to do this manually because your update is not yet available (or you want to live on the wild side). In my case I also wanted to retain my rooted status of my phone and unfortunately the app that does the update and retaining root all in one step (Mobile ODIN) is not supporting the i9500.
I downloaded the official Samsung ROM update for 4.3 for South Africa from the Sammobile site (www.sammobile.com/firmwares/).
I followed the instructions at android.sc/update-samsung-galaxy-s4-i9500-with-official-a... to flash the updated ROM to my device. It rebooted fine with its original apps and files in place, along with even the Google Launcher that I had just installed a day ago. Always let the phone finish its first reboot without interruption (unless you see an error message) as the first reboot will take a little longer than normal.
I followed the instructions at www.ibtimes.co.uk/articles/520949/20131110/galaxys4-i9500... to get my root access back. Only odd thing is that with KNOX now installed it warns about some low level apps being blocked for root access so I followed the tip at the bottom of the page (www.theandroidsoul.com/root-galaxy-s4-lte-i9505-on-androi...) to freeze these notifications out. Non-root users won't worry about this.