I've tried lots of stuff the operator suggested and replaced the SIM etc. etc. In the end I got fed up and swapped back to my SGS2, which is works fine, and intended to swap the SGS4 for another one. But since moving to the SGS2, the the 4.3 OTA update has been released. I've NOT moved to 4.3 and it comes up with the new software available message every few hours.
On all my other Android devices I've rooted them and to make use of TiB and other neat tools. I haven't done that with the SGS4 yet but would like to once it's out of warranty.
So my dilemma is this...
Should I send the SGS4 back and get another from the operator and risk getting a 4.3 KNOX device, or
Should I send it to a Samsung service centre (as folks in the thread I referenced suggest) and risk that the service centre updating my phone to 4.3, or
Should I root and update to 4.3 without updating the modem etc. to avoid KNOX and see if the new OS fixes my problems but risk my warranty (which runs until May 2015)?
I'm kicking myself for not getting on with this months ago before 4.3 was released. Any views gratefully received.