Nope. I was flashing an official firmware which doesn't effect Knox at all. Added to the fact the firmware I flashed was for the model / region version of my device means it was just a case of putting the firmware that would have been available to me on Kies before they stopped its rollout.
So yeah still 100% official and no warranty issues.
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I just think it looks dated. Its not terrible but just stands ajar, especially when the rest of the apps are materialised.
I'm surprised you guys don't use SwiftKey. Especially now that is free. Or better yet, use Super SwiftKey on XDA. The devs added a tonne of custom themes. Here's my current favorite theme.