Do not use red for the icon color of the pro version
I love SafeInCloud but every time I look at the red icon on my iPhone I think "sync error" rather than pro version. I would prefer the same blue as on desktop computer but if another color is necessary green would be less jarring. Actually red would make an excellent indicator for lack of synchronization.
Michal Švantner commented
Absolutely agree, please, use blue (the best) or green, but not red ...