Knox question - flashing previous OTA version, no kernel update

I've been googling this for a while and haven't found anything conclusive. Some sources say this won't trip knox, other sources say it will.

Can I flash an official,stock .zip of the previous build number, N900VVRUEOB6, over top of the newest build number, N900VVUREFOF1, without tripping knox? My phone updated itself - the nag screen appeared after unlocking and my phone immediately rebooted and installed the update.

Would this void my warranty? I have read that using Odin would definitely trip knox, so I would be flashing the zip from recovery mode. There is no kernel update involved so it should allow me to do this.

Is there any other way to roll back the security update that fixed stagefright?

Any previous Galaxy S3 owners?

what are the big differences between the two?
I am especially concerned about the battery life, which doesn't seem to be too good on the Zenfone 2