Change effective on 24 September 2019
The Ruby Buildpack now includes Bundler 1.17.3. Applications specifying Bundler 1.x in their
Gemfile.lock will now receive bundler: 1.17.3.
We’ve received reports that there is a bug with this version of Bundler and Ruby 2.6.0 and 2.6.1. If you’re using one of these versions please update your Ruby version to 2.6.3+. The issue looks related to this bug report but has a different failure mode. We are still investigating.