I noticed a tiny change on the iPhone availability website. At first I was puzzled and then I remembered. Yesterday Apple had a red circle and a green circle to show availability. Today they updated the site with a tiny change:
The red circle was replaced with a red square. Users with color blindness have trouble seeing the differences between these colors so the shape helps. This reminded me of a couple places in my own designs where I wasn’t considering colorblindness. There are many different types of color blindness. One quick check is to print your designs in black and white and make sure they still make sense.