These four are from 2015. Just like Ian Happ this year, in 2015 Chrome Update included two cards for Addison Russell.
The 2016 version of Chrome Update included just three Cubs.
One thing you may have noticed from both years is the extra sparkle look on the cards. It seems odd to me to change the look of Chrome cards for Update, but whatever. Cardboard Connection refers to the look as a Bubble/Pulsar Refractor finish.