Default [Q] Firmware v4.3 WITHOUT Knox

Hi there,

Is it possible to install Android version 4.3 WITHOUT also installing the Knox bootloader?

I've just purchased a brand new S4 i9505. I'm running 4.2 with no Knox bootloader installed. I would like to upgrade to v4.3 but still retain the ability to downgrade to previous ROM versions. Is this possible?

Many thanks for any information you can provide.