OMG! Ubuntu! posted How To Install Unity Mail on Ubuntu 16.04
A quote from the article:
Do you remember a small little Ubuntu app called Unity Mail? A small app, it let you see the number of unread messages in your Gmail (or other webmail) account on the Unity launcher without the (comparative) hassle of setting up or running a fully fledged desktop e-mail app. Not ringing any bells? Theres a reason for that.How To Install Unity Mail on Ubuntu 16.04 @ OMG! Ubuntu!