Pending Notifications icons are black and white (no color) I have a Nexus 5. 

All of the sudden I've noticed that the pending notifications icons at the top left of the my phone are black and white instead of some of them being colored. I don't know what happened. I didn't change any settings in the past couple of days. The only thing I've done is installed Yahoo News digest App. 

Is there a setting that I could double check or someplace on my phone that addresses this problem?
According to the official design guide, notification icons are supposed to be white only.

Some apps do break the rules, so perhaps it's just that you had an app that used to have colourful icons but was updated to bring it into line with the rules.