You can go to the twrp homepage (link in the first post) and download the latest version of it in the .tar file so you can flash it using odin. That's what I did and it worked fine. The backup and restore work fine in this version too as I've found out by playing around with a few mods that evidently don't work in MJ4. I've looped it 3 or 4 times, wiped, and restored and it is working fine now.
As for knox, there's a program you can use to freeze the know notifier for you if you don't want to do it manually. I used it to see what it froze and all it did was the knox notifier. You can either do it yourself or use this and it will do it for you. Either way it stops the annoying message in its tracks.
[APP][v1.0.1][10.13.13]KNOX Disabler - Easily disable KNOX notifications! - xda-developers
Sorry for my message earlier. I just hadn't seen anyone post in this forum in weeks so I was afraid your question would go unanswered.
It's all good.