Different android versions are: cupcake, donut, eclairs, froyo, gringerbread, honeycomb, ice cream sandwich, jelly bean, kitkat, lollipop.
If you can see the new version starts with the just next alphabatic letter (c,d,e,f,g,h,i,j,k,l) . The latest androis os available in smartphone is Lollipop 5.1.