We are spending ~4.5 minutes per build now installing Ruby 2.3.3, since it isn’t in the image. This is killing us! Please prioritize language updates like this: we shouldn’t have to suffer a 25% hit just to keep up with the latest ruby.
Or at the very least, please make it a priority to support whatever Heroku is supporting. Heroku releases support for ruby point releases the same day they come out.