Notify supports Blender 2.7x and Blender 2.80. Notify Sends a system notification when your render is complete, works on linux and theoretically on Windows too, havent tested it there yet.

How to install:

1. Clone or Download the github
   
2. Extract files anywhere
   
3. Open Blender
   
4. Go to file / user preferences
   
5. Click on the Add-on tab
   
6. Hit install from file
   
7. Locate the send_notify_2-8x.py or send_notify_2-7x.py (depending on your blender version)
   
8. Check the box next to "system: notify" on your add-ons tab
   
9. Save user settings.

Notify now supports notifications in 7 lenguages: English, Spanish, Catalan, Italian, French, German and Portuguese.
Notify will auto detect the sytem lenguage.

Missing/upcomming features: options to send sms and e-mail notifications.