Google Android operating systems are always named after sweet treats, and in alphabetical order. So far we've had Cupcake, Donut, Eclair, Froyo, Gingerbread, Honeycomb, Ice Cream Sandwich, Jelly Bean, KitKat, Lollipop, Marshmallow and Nougat.
The latest OS update is almost certainly going to be called Oreo, following a fairly large slip-up on Google+ that was captured by Android Police. It originally uploaded a teaser that included Oreo in the file name, but upon realising its error replaced it with one containing the name Octopus.
Despite also teasing us with an octopus easter egg in the latest public beta (go to to Settings, About Phone and tap Android version multiple times), Google's own Hiroshi Lockheimer has previously posted several Twitter teasers hinting at the name Oreo, and it's the clear favourite