Heroku-16 and Heroku-18 Stack Images Updated

Change effective on 09 December 2019

We have updated the heroku-16 and heroku-18 stack images to pick up security fixes in upstream packages. The new stack images will be rolled out automatically in the next 24 hours. You do not need to redeploy your app or manually restart your dynos.

See this Dev Center article for an overview of the packages available in each stack image.